+ $qty = $reverse ? -$line_item->quantity : $line_item->quantity;
+
+ $qtys[$line_item->stock_id]['qty'] = $qty + @$qtys[$line_item->stock_id]['qty'];
+ $qtys[$line_item->stock_id]['line'] = $line_no;
+ }
+
+ foreach($qtys as $stock_id => $sum)
+ {
+ $fail = check_negative_stock($stock_id, $sum['qty'], $location, $date_);
+ if ($fail)
+ $low_stock[] = $stock_id;