Rounding errors in tax calculations for tax_included sales fixed again.

diff --git a/taxes/tax_calc.inc b/taxes/tax_calc.inc
index 4ed7015f7812b6bdd229b737eb9a1ad5a3d89cee..4c4b9f37c5a7ea047e6a4d908d3a3c7f5502c107 100644 (file)
--- 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);