diff --git a/htdocs/comm/propal.php b/htdocs/comm/propal.php
index 5406ba72a26..51057ec3af4 100644
--- a/htdocs/comm/propal.php
+++ b/htdocs/comm/propal.php
@@ -759,8 +759,11 @@ if (empty($reshook))
 						$pu_ttc = $prod->multiprices_ttc[$object->thirdparty->price_level];
 						$price_min = $prod->multiprices_min[$object->thirdparty->price_level];
 						$price_base_type = $prod->multiprices_base_type[$object->thirdparty->price_level];
-						if (isset($prod->multiprices_tva_tx[$object->thirdparty->price_level])) $tva_tx=$prod->multiprices_tva_tx[$object->thirdparty->price_level];
-						if (isset($prod->multiprices_recuperableonly[$object->thirdparty->price_level])) $tva_npr=$prod->multiprices_recuperableonly[$object->thirdparty->price_level];
+						if (! empty($conf->global->PRODUIT_MULTIPRICES_USE_VAT_PER_LEVEL))  // using this option is a bug. kept for backward compatibility
+						{
+						  if (isset($prod->multiprices_tva_tx[$object->thirdparty->price_level])) $tva_tx=$prod->multiprices_tva_tx[$object->thirdparty->price_level];
+						  if (isset($prod->multiprices_recuperableonly[$object->thirdparty->price_level])) $tva_npr=$prod->multiprices_recuperableonly[$object->thirdparty->price_level];
+						}
 					}
 					elseif (! empty($conf->global->PRODUIT_CUSTOMER_PRICES))
 					{
diff --git a/htdocs/commande/card.php b/htdocs/commande/card.php
index e13381677c0..ebe2b58745d 100644
--- a/htdocs/commande/card.php
+++ b/htdocs/commande/card.php
@@ -657,10 +657,11 @@ if (empty($reshook))
 						$pu_ttc = $prod->multiprices_ttc[$object->thirdparty->price_level];
 						$price_min = $prod->multiprices_min[$object->thirdparty->price_level];
 						$price_base_type = $prod->multiprices_base_type[$object->thirdparty->price_level];
-						if (isset($prod->multiprices_tva_tx[$object->client->price_level])) $tva_tx=$prod->multiprices_tva_tx[$object->client->price_level];
-						if (isset($prod->multiprices_recuperableonly[$object->client->price_level])) $tva_npr=$prod->multiprices_recuperableonly[$object->client->price_level];
-						$tva_tx=$prod->multiprices_tva_tx[$object->thirdparty->price_level];
-						$tva_npr=$prod->multiprices_recuperableonly[$object->thirdparty->price_level];
+						if (! empty($conf->global->PRODUIT_MULTIPRICES_USE_VAT_PER_LEVEL))  // using this option is a bug. kept for backward compatibility
+						{
+						  if (isset($prod->multiprices_tva_tx[$object->thirdparty->price_level])) $tva_tx=$prod->multiprices_tva_tx[$object->thirdparty->price_level];
+						  if (isset($prod->multiprices_recuperableonly[$object->thirdparty->price_level])) $tva_npr=$prod->multiprices_recuperableonly[$object->thirdparty->price_level];
+						}
 					}
 					elseif (! empty($conf->global->PRODUIT_CUSTOMER_PRICES))
 					{