diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 01e8acf4896..0084a4a33c8 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -4784,7 +4784,7 @@ function price2num($amount, $rounding = '', $option = 0)
 		$nbofdectoround = '';
 		if ($rounding == 'MU')     $nbofdectoround = $conf->global->MAIN_MAX_DECIMALS_UNIT;
 		elseif ($rounding == 'MT') $nbofdectoround = $conf->global->MAIN_MAX_DECIMALS_TOT;
-		elseif ($rounding == 'MS') $nbofdectoround = empty($conf->global->MAIN_MAX_DECIMALS_STOCK) ? 5 : $conf->global->MAIN_MAX_DECIMALS_STOCK;
+		elseif ($rounding == 'MS') $nbofdectoround = !isset($conf->global->MAIN_MAX_DECIMALS_STOCK) ? 5 : $conf->global->MAIN_MAX_DECIMALS_STOCK;
 		elseif ($rounding == 'CR') $nbofdectoround = 8;
 		elseif (is_numeric($rounding))  $nbofdectoround = $rounding;
 		//print "RR".$amount.' - '.$nbofdectoround.'<br>';