Help With Promotion

i am develop my promotion addon bonus is : Order discount by fixed

its working well but when customer place order from different vendors. cs-cart doesnt calculate sub orders discounts. then doesnt show discount with orders details.

if order is come from one seller working without problem


i double check promotions.fn

fn_promotions_calculate_order_discount in this function

if (empty($cart['parent_order_id'])) {

HERE is put parent order promotion infos

but after else doesnt do any action ?

what should I pay attention to ?