diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 023adfae7a5..0618e15afe8 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -2747,23 +2747,23 @@ class Form
 					}
 					if ($objp->quantity == 1)
 					{
-						$opt.= price($objp->fprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/";
-						$outval.= price($objp->fprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/";
+						$opt.= price($objp->fprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/";
+						$outval.= price($objp->fprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/";
 						$opt.= $langs->trans("Unit");	// Do not use strtolower because it breaks utf8 encoding
 						$outval.=$langs->transnoentities("Unit");
 					}
 					else
 					{
-						$opt.= price($objp->fprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$objp->quantity;
-						$outval.= price($objp->fprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/".$objp->quantity;
+						$opt.= price($objp->fprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$objp->quantity;
+						$outval.= price($objp->fprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/".$objp->quantity;
 						$opt.= ' '.$langs->trans("Units");	// Do not use strtolower because it breaks utf8 encoding
 						$outval.= ' '.$langs->transnoentities("Units");
 					}
 
 					if ($objp->quantity >= 1)
 					{
-						$opt.=" (".price($objp->unitprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$langs->trans("Unit").")";	// Do not use strtolower because it breaks utf8 encoding
-						$outval.=" (".price($objp->unitprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/".$langs->transnoentities("Unit").")";	// Do not use strtolower because it breaks utf8 encoding
+						$opt.=" (".price($objp->unitprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$langs->trans("Unit").")";	// Do not use strtolower because it breaks utf8 encoding
+						$outval.=" (".price($objp->unitprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 0, $langs, 0, 0, -1, $conf->currency)."/".$langs->transnoentities("Unit").")";	// Do not use strtolower because it breaks utf8 encoding
 					}
 					if ($objp->remise_percent >= 1)
 					{
@@ -2914,7 +2914,7 @@ class Form
 					}
 					if ($objp->quantity == 1)
 					{
-						$opt.= price($objp->fprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/";
+						$opt.= price($objp->fprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/";
 					}
 
 					$opt.= $objp->quantity.' ';
@@ -2930,7 +2930,7 @@ class Form
 					if ($objp->quantity > 1)
 					{
 						$opt.=" - ";
-						$opt.= price($objp->unitprice * ($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$langs->trans("Unit");
+						$opt.= price($objp->unitprice * (!empty($conf->global->DISPLAY_DISCOUNTED_SUPPLIER_PRICE)?(1 - $objp->remise_percent / 100):1), 1, $langs, 0, 0, -1, $conf->currency)."/".$langs->trans("Unit");
 					}
 					if ($objp->duration) $opt .= " - ".$objp->duration;
 					$opt .= "</option>\n";