diff --git a/application/models/Sale.php b/application/models/Sale.php
index 3bcbdf603..deaffc089 100644
--- a/application/models/Sale.php
+++ b/application/models/Sale.php
@@ -686,22 +686,22 @@ class Sale extends CI_Model
 	{
 		if($this->config->item('tax_included'))
 		{
-			$total    = '1';
-			$subtotal = '(1 - (SUM(1 - 100 / (100 + sales_items_taxes.percent))))';
-			$tax      = '(SUM(1 - 100 / (100 + sales_items_taxes.percent)))';
+			$sale_total = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_subtotal = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (100 / (100 + SUM(sales_items_taxes.percent))))';
+			$sale_tax = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 - 100 / (100 + SUM(sales_items_taxes.percent))))';
 		}
 		else
 		{
-			$tax      = '(SUM(sales_items_taxes.percent) / 100)';
-			$total    = '(1 + (SUM(sales_items_taxes.percent / 100)))';
-			$subtotal = '1';
+			$sale_total = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 + (SUM(sales_items_taxes.percent) / 100)))';
+			$sale_subtotal = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_tax = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (SUM(sales_items_taxes.percent) / 100))';
 		}
 
-		$sale_total = '(sales_items.item_unit_price * sales_items.quantity_purchased - sales_items.item_unit_price * sales_items.quantity_purchased * sales_items.discount_percent / 100)';
 		$sale_cost  = '(sales_items.item_cost_price * sales_items.quantity_purchased)';
 
-		$decimals = totals_decimals();
-		
+		// increase the rounding of two decimals on top of the selected ones to avoid accumulative rounding errors in the totals
+		$decimals = totals_decimals() + 2;
+
 		if(empty($input['sale_id']))
 		{
 			$where = 'WHERE DATE(sales.sale_time) BETWEEN ' . $this->db->escape($inputs['start_date']) . ' AND ' . $this->db->escape($inputs['end_date']);
@@ -762,11 +762,11 @@ class Sale extends CI_Model
 					payments.sale_payment_amount,
 					IFNULL(SUM(sales_items_taxes.percent), 0) AS item_tax_percent,
 					' . "
-					IFNULL(ROUND($sale_total * $total, $decimals), ROUND($sale_total * $subtotal, $decimals)) AS total,
-					IFNULL(ROUND($sale_total * $tax, $decimals), 0) AS tax,
-					ROUND($sale_total * $subtotal, $decimals) AS subtotal,
-					ROUND($sale_total - $sale_cost, $decimals) AS profit,
-					ROUND($sale_cost, $decimals) AS cost
+					ROUND($sale_subtotal, $decimals) AS subtotal,
+					IFNULL(ROUND($sale_total, $decimals), ROUND($sale_subtotal, $decimals)) AS total,
+					IFNULL(ROUND($sale_tax, $decimals), 0) AS tax,
+					ROUND($sale_cost, $decimals) AS cost,
+					ROUND($sale_total - IFNULL($sale_tax, 0) - $sale_cost, $decimals) AS profit
 					" . '
 				FROM ' . $this->db->dbprefix('sales_items') . ' AS sales_items
 				INNER JOIN ' . $this->db->dbprefix('sales') . ' AS sales
diff --git a/application/models/reports/Detailed_sales.php b/application/models/reports/Detailed_sales.php
index c8391b8ed..ac2ac4fe3 100644
--- a/application/models/reports/Detailed_sales.php
+++ b/application/models/reports/Detailed_sales.php
@@ -6,13 +6,13 @@ class Detailed_sales extends Report
 	{
 		parent::__construct();
 	}
-	
+
 	public function create(array $inputs)
 	{
 		//Create our temp tables to work with the data in our report
 		$this->Sale->create_temp_table($inputs);
 	}
-	
+
 	public function getDataColumns()
 	{
 		return array(
@@ -44,7 +44,7 @@ class Detailed_sales extends Report
 				$this->lang->line('reports_discount'))
 		);		
 	}
-	
+
 	public function getDataBySaleId($sale_id)
 	{
 		$this->db->select('sale_id, sale_date, SUM(quantity_purchased) AS items_purchased, employee_name, customer_name, SUM(subtotal) AS subtotal, SUM(total) AS total, SUM(tax) AS tax, SUM(cost) AS cost, SUM(profit) AS profit, payment_type, comment');
@@ -53,7 +53,7 @@ class Detailed_sales extends Report
 
 		return $this->db->get()->row_array();
 	}
-	
+
 	public function getData(array $inputs)
 	{
 		$this->db->select('sale_id, sale_date, SUM(quantity_purchased) AS items_purchased, employee_name, customer_name, SUM(subtotal) AS subtotal, SUM(total) AS total, SUM(tax) AS tax, SUM(cost) AS cost, SUM(profit) AS profit, payment_type, comment');
@@ -79,7 +79,7 @@ class Detailed_sales extends Report
 		$data = array();
 		$data['summary'] = $this->db->get()->result_array();
 		$data['details'] = array();
-		
+
 		foreach($data['summary'] as $key=>$value)
 		{
 			$this->db->select('name, category, quantity_purchased, item_location, serialnumber, description, subtotal, total, tax, cost, profit, discount_percent');
@@ -87,10 +87,10 @@ class Detailed_sales extends Report
 			$this->db->where('sale_id', $value['sale_id']);
 			$data['details'][$key] = $this->db->get()->result_array();
 		}
-		
+
 		return $data;
 	}
-	
+
 	public function getSummaryData(array $inputs)
 	{
 		$this->db->select('SUM(subtotal) AS subtotal, SUM(total) AS total, SUM(tax) AS tax, SUM(cost) AS cost, SUM(profit) AS profit');
diff --git a/application/models/reports/Summary_categories.php b/application/models/reports/Summary_categories.php
index 482de4914..dbd34594f 100644
--- a/application/models/reports/Summary_categories.php
+++ b/application/models/reports/Summary_categories.php
@@ -21,10 +21,9 @@ class Summary_categories extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->commonFrom();
+
 		$this->db->join('items AS items', 'sales_items.item_id = items.item_id', 'inner');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_customers.php b/application/models/reports/Summary_customers.php
index bbe7accf9..a479e8f61 100644
--- a/application/models/reports/Summary_customers.php
+++ b/application/models/reports/Summary_customers.php
@@ -21,10 +21,9 @@ class Summary_customers extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->commonFrom();
+
 		$this->db->join('people AS customer_p', 'sales.customer_id = customer_p.person_id');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_employees.php b/application/models/reports/Summary_employees.php
index e42f05d45..1cc275670 100644
--- a/application/models/reports/Summary_employees.php
+++ b/application/models/reports/Summary_employees.php
@@ -21,10 +21,9 @@ class Summary_employees extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->commonFrom();
+
 		$this->db->join('people AS employee_p', 'sales.employee_id = employee_p.person_id');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_items.php b/application/models/reports/Summary_items.php
index 4a2c3ffa1..9da526a58 100644
--- a/application/models/reports/Summary_items.php
+++ b/application/models/reports/Summary_items.php
@@ -21,10 +21,9 @@ class Summary_items extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->commonFrom();
+
 		$this->db->join('items AS items', 'sales_items.item_id = items.item_id', 'inner');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_report.php b/application/models/reports/Summary_report.php
index b1e40c1ff..2e4b9dd1e 100644
--- a/application/models/reports/Summary_report.php
+++ b/application/models/reports/Summary_report.php
@@ -9,33 +9,56 @@ abstract class Summary_report extends Report
 
 	protected function commonSelect(array $inputs)
 	{
+		// create a temporary table to contain all the payment types and amount
+		$this->db->query('CREATE TEMPORARY TABLE IF NOT EXISTS ' . $this->db->dbprefix('sales_items_taxes_temp') . 
+			' (INDEX(sale_id), INDEX(item_id))
+			(
+				SELECT sales_items_taxes.sale_id AS sale_id,
+					sales_items_taxes.item_id AS item_id,
+					SUM(sales_items_taxes.percent) AS percent
+				FROM ' . $this->db->dbprefix('sales_items_taxes') . ' AS sales_items_taxes
+				INNER JOIN ' . $this->db->dbprefix('sales') . ' AS sales
+					ON sales.sale_id = sales_items_taxes.sale_id
+				INNER JOIN ' . $this->db->dbprefix('sales_items') . ' AS sales_items
+					ON sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.line = sales_items_taxes.line
+				WHERE DATE(sale_time) BETWEEN ' . $this->db->escape($inputs['start_date']) . ' AND ' . $this->db->escape($inputs['end_date']) . '
+				GROUP BY sales_items_taxes.sale_id, sales_items_taxes.item_id
+			)'
+		);
+
 		if($this->config->item('tax_included'))
 		{
-			$total    = '1';
-			$subtotal = '(1 - (SUM(1 - 100 / (100 + sales_items_taxes.percent))))';
-			$tax      = '(SUM(1 - 100 / (100 + sales_items_taxes.percent)))';
+			$sale_total = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_subtotal = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (100 / (100 + sales_items_taxes.percent)))';
+			$sale_tax = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 - 100 / (100 + sales_items_taxes.percent)))';
 		}
 		else
 		{
-			$tax      = '(SUM(sales_items_taxes.percent) / 100)';
-			$total    = '(1 + (SUM(sales_items_taxes.percent / 100)))';
-			$subtotal = '1';
+			$sale_total = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 + (sales_items_taxes.percent / 100)))';
+			$sale_subtotal = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_tax = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (sales_items_taxes.percent / 100))';
 		}
 
-		$sale_total = 'SUM(sales_items.item_unit_price * sales_items.quantity_purchased - sales_items.item_unit_price * sales_items.quantity_purchased * sales_items.discount_percent / 100)';
-		$sale_cost  = 'SUM(sales_items.item_cost_price * sales_items.quantity_purchased)';
+		$sale_cost = 'SUM(sales_items.item_cost_price * sales_items.quantity_purchased)';
 
 		$decimals = totals_decimals();
 
 		$this->db->select("
-				ROUND($sale_total * $subtotal, $decimals) AS subtotal,
-				IFNULL(ROUND($sale_total * $total, $decimals), ROUND($sale_total * $subtotal, $decimals)) AS total,
-				IFNULL(ROUND($sale_total * $tax, $decimals), 0) AS tax,
+				ROUND($sale_subtotal, $decimals) AS subtotal,
+				IFNULL(ROUND($sale_total, $decimals), ROUND($sale_subtotal, $decimals)) AS total,
+				IFNULL(ROUND($sale_tax, $decimals), 0) AS tax,
 				ROUND($sale_cost, $decimals) AS cost,
-				ROUND($sale_total - $sale_cost, $decimals) AS profit
+				ROUND($sale_total - IFNULL($sale_tax, 0) - $sale_cost, $decimals) AS profit
 		");
 	}
-	
+
+	protected function commonFrom()
+	{
+		$this->db->from('sales_items AS sales_items');
+		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->db->join('sales_items_taxes_temp AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id', 'left outer');
+	}
+
 	protected function commonWhere(array $inputs)
 	{
 		$this->db->where('DATE(sales.sale_time) BETWEEN ' . $this->db->escape($inputs['start_date']) . ' AND ' . $this->db->escape($inputs['end_date']));
@@ -54,14 +77,12 @@ abstract class Summary_report extends Report
             $this->db->where('quantity_purchased < 0');
         }
 	}
-	
+
 	public function getSummaryData(array $inputs)
 	{
 		$this->commonSelect($inputs);
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
+		$this->commonFrom();
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_sales.php b/application/models/reports/Summary_sales.php
index 9fd6027ae..fafb3da51 100644
--- a/application/models/reports/Summary_sales.php
+++ b/application/models/reports/Summary_sales.php
@@ -21,12 +21,10 @@ class Summary_sales extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
+		$this->commonFrom();
 
 		$this->commonWhere($inputs);   
-        
+
 		$this->db->group_by('sale_date');
 		$this->db->order_by('sale_date');
 
diff --git a/application/models/reports/Summary_suppliers.php b/application/models/reports/Summary_suppliers.php
index f91e521b0..b073bef4d 100644
--- a/application/models/reports/Summary_suppliers.php
+++ b/application/models/reports/Summary_suppliers.php
@@ -21,12 +21,11 @@ class Summary_suppliers extends Summary_report
 				SUM(sales_items.quantity_purchased) AS quantity_purchased
 		');
 
-		$this->db->from('sales_items AS sales_items');
-		$this->db->join('sales AS sales', 'sales_items.sale_id = sales.sale_id', 'inner');
+		$this->commonFrom();
+
 		$this->db->join('items AS items', 'sales_items.item_id = items.item_id', 'inner');
 		$this->db->join('suppliers AS supplier_c', 'supplier_c.person_id = items.supplier_id');
 		$this->db->join('people AS supplier_p', 'supplier_c.person_id = supplier_p.person_id');
-		$this->db->join('sales_items_taxes AS sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line', 'left outer');
 
 		$this->commonWhere($inputs);
 
diff --git a/application/models/reports/Summary_taxes.php b/application/models/reports/Summary_taxes.php
index 045b16dd0..f57fb696b 100644
--- a/application/models/reports/Summary_taxes.php
+++ b/application/models/reports/Summary_taxes.php
@@ -29,36 +29,37 @@ class Summary_taxes extends Summary_report
 			$quantity_cond .= 'AND item_location = '. $this->db->escape($inputs['location_id']);
 		}
 
-		if ($this->config->item('tax_included'))
+		if($this->config->item('tax_included'))
 		{
-			$total    = '1';
-			$subtotal = '(100/(100+percent))';
-			$tax      = '(1 - (100/(100 +percent)))';
+			$sale_total = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_subtotal = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (100 / (100 + sales_items_taxes.percent)))';
+			$sale_tax = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 - 100 / (100 + sales_items_taxes.percent)))';
 		}
 		else
 		{
-			$tax      = '(percent/100)';
-			$total    = '(1+(percent/100))';
-			$subtotal = '1';
+			$sale_total = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (1 + (sales_items_taxes.percent / 100)))';
+			$sale_subtotal = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100))';
+			$sale_tax = '(sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount_percent / 100) * (sales_items_taxes.percent / 100))';
 		}
 
 		$decimals = totals_decimals();
 
-		$query = $this->db->query("SELECT percent, count(*) AS count, SUM(subtotal) AS subtotal, SUM(total) AS total, SUM(tax) AS tax
+		$query = $this->db->query("SELECT percent, count(*) AS count, ROUND(SUM(subtotal), $decimals) AS subtotal, ROUND(SUM(total), $decimals) AS total, ROUND(SUM(tax), $decimals) AS tax
 			FROM (
 				SELECT
-					CONCAT(ROUND(percent, $decimals), '%') AS percent,
-					ROUND((item_unit_price * quantity_purchased - item_unit_price * quantity_purchased * discount_percent /100) * $subtotal, $decimals) AS subtotal,
-					ROUND((item_unit_price * quantity_purchased - item_unit_price * quantity_purchased * discount_percent /100) * $total, $decimals) AS total,
-					ROUND((item_unit_price * quantity_purchased - item_unit_price * quantity_purchased * discount_percent /100) * $tax, $decimals) AS tax
-					FROM ".$this->db->dbprefix('sales_items_taxes')."
-					JOIN ".$this->db->dbprefix('sales_items')." ON "
-						.$this->db->dbprefix('sales_items').'.sale_id='.$this->db->dbprefix('sales_items_taxes').'.sale_id'." AND "
-						.$this->db->dbprefix('sales_items').'.item_id='.$this->db->dbprefix('sales_items_taxes').'.item_id'." AND "
-						.$this->db->dbprefix('sales_items').'.line='.$this->db->dbprefix('sales_items_taxes').'.line'." 
-					JOIN ".$this->db->dbprefix('sales')." ON ".$this->db->dbprefix('sales_items_taxes').".sale_id=".$this->db->dbprefix('sales').".sale_id
-					WHERE date(sale_time) BETWEEN " . $this->db->escape($inputs['start_date']) . " AND " . $this->db->escape($inputs['end_date']) . " $quantity_cond) AS temp_taxes
-					GROUP BY percent");
+					CONCAT(IFNULL(ROUND(percent, $decimals), 0), '%') AS percent,
+					$sale_subtotal AS subtotal,
+					IFNULL($sale_total, $sale_subtotal) AS total,
+					IFNULL($sale_tax, 0) AS tax
+					FROM " . $this->db->dbprefix('sales_items') . ' AS sales_items
+					INNER JOIN ' . $this->db->dbprefix('sales') . ' AS sales
+						ON sales_items.sale_id = sales.sale_id
+					LEFT OUTER JOIN ' . $this->db->dbprefix('sales_items_taxes') . ' AS sales_items_taxes
+						ON sales_items.sale_id = sales_items_taxes.sale_id AND sales_items.item_id = sales_items_taxes.item_id AND sales_items.line = sales_items_taxes.line
+					WHERE DATE(sale_time) BETWEEN ' . $this->db->escape($inputs['start_date']) . ' AND ' . $this->db->escape($inputs['end_date']) . " $quantity_cond
+				) AS temp_taxes
+			GROUP BY percent"
+		);
 
 		return $query->result_array();
 	}