From: Janusz Dobrowolski <janusz@frontaccouting.eu>
Date: Sun, 28 Aug 2011 20:28:00 +0000 (+0200)
Subject: Rounding errors in tax calculations for tax_included sales fixed again.
X-Git-Tag: 2.3-final~577
X-Git-Url: https://delta.frontaccounting.com/gitweb/?a=commitdiff_plain;h=d310e2d17d5aa54ce118b9e70890ce1f257737fd;p=fa-stable.git

Rounding errors in tax calculations for tax_included sales fixed again.
---

diff --git a/taxes/tax_calc.inc b/taxes/tax_calc.inc
index 4ed7015f..4c4b9f37 100644
--- a/taxes/tax_calc.inc
+++ b/taxes/tax_calc.inc
@@ -39,17 +39,20 @@ function get_tax_free_price_for_item($stock_id, $price, $tax_group, $tax_include
 	// if no exemptions or taxgroup is empty, then no included/excluded taxes
 	if ($tax_array == null)
 		return $price;
-	
-	$tax_multiplier = 0;
-
-	// loop for all taxes
 
+	// to avoid rounding errors we have to just subtract taxes from tax_included price.
+	$tax_multiplier = 0;
 	foreach ($tax_array as $taxitem) 
 	{
 		$tax_multiplier += $taxitem["rate"];
 	}
 
-	return round($price / (1 + ($tax_multiplier / 100)),  user_price_dec());
+	$tax = 0;
+	foreach ($tax_array as $taxitem)
+	{
+		$tax += round($price*$taxitem['rate']/(100+$tax_multiplier), user_price_dec());
+	}
+	return $price-$tax;
 }
 //
 //	Full price (incl. VAT) for item $stock_id with line price $price,
@@ -76,7 +79,7 @@ function get_full_price_for_item($stock_id, $price, $tax_group, $tax_included, $
 	if ($tax_array == null)
 		return $price;
 	
-	$tax_multiplier = 0;	
+	$tax_multiplier = 0;
 
 	// loop for all items
 
@@ -115,7 +118,7 @@ function get_taxes_for_item($stock_id, $tax_group_items_array)
 	foreach ($tax_group_items_array as $tax_group_item) 
 	{ 
 		
-		$skip = false;			
+		$skip = false;
 		
 		// if it's in the exemptions, skip
 		foreach ($item_tax_type_exemptions as $exemption) 
@@ -157,15 +160,18 @@ function get_tax_for_items($items, $prices, $shipping_cost, $tax_group, $tax_inc
 		$item_taxes = get_taxes_for_item($items[$i], $ret_tax_array);
 		if ($item_taxes != null) 
 		{
+			$tax_multiplier = 0;
+			foreach ($item_taxes as $taxitem) 
+			{
+				$tax_multiplier += $taxitem['rate'];
+			}
 			foreach ($item_taxes as $item_tax) 
 			{
 				if ($item_tax['rate'] !== null) {
 					$index = $item_tax['tax_type_id'];
 					if ($tax_included == 1) {
-					  $nprice = get_tax_free_price_for_item($items[$i], $prices[$i], $tax_group, $tax_included, null, $item_tax['tax_type_id']);
-					  //$ret_tax_array[$index]['Value'] += round2($prices[$i] - $nprice, $dec);
-					  $ret_tax_array[$index]['Value'] += round2($nprice*$item_tax['rate']/100, $dec);
-					  $ret_tax_array[$index]['Net'] += $nprice;
+					  $ret_tax_array[$index]['Value'] += round2($prices[$i]*$item_tax['rate']/(100+$tax_multiplier), $dec);
+					  $ret_tax_array[$index]['Net'] += round2($prices[$i]*100/(100+$tax_multiplier), $dec);
 					} else {
 					  $ret_tax_array[$index]['Value'] += ($prices[$i] * $item_tax['rate'] / 100);
 					  $ret_tax_array[$index]['Net'] += $prices[$i];
@@ -191,15 +197,14 @@ function get_tax_for_items($items, $prices, $shipping_cost, $tax_group, $tax_inc
 						$tax_rate += $item_tax['rate'];
 					}
 				}
-				$shipping_net = round2($shipping_cost / (1 + ($tax_rate / 100)), $dec);
+				$shipping_net = round2($shipping_cost*100/(100+$tax_rate), $dec);
 			}
 			foreach ($item_taxes as $item_tax) 
 			{
 				$index = $item_tax['tax_type_id'];
 				if ($item_tax['rate'] !== null && $ret_tax_array[$index]['rate'] !== null) {
 					  if($tax_included==1) {
-					    //$ret_tax_array[$index]['Value'] += round2($shipping_cost - $shipping_net, $dec);
-						$ret_tax_array[$index]['Value'] += round2($shipping_net * $item_tax['rate'] / 100, $dec);
+					    $ret_tax_array[$index]['Value'] += round2($shipping_cost*$item_tax['rate']/(100+$tax_rate), $dec);
 					    $ret_tax_array[$index]['Net'] += $shipping_net;
 					  } else {
 						$ret_tax_array[$index]['Value'] += ($shipping_cost * $item_tax['rate'] / 100);