Why is the discount not considered when placing an order in Bitrix?

Question

1C-Bitrix

Hello.
I have discounts for certain products.
I place an order via CSaleOrder::Add. Everything works well, but the order gets the cost without a discount. At the same time, the user receives a notification by mail, where the cost of the goods is indicated taking into account the discount.
I tried to make registration on D7, all the same, the goods get into the order with the regular price.
I've searched a lot and can't find a solution to the problem. Ready to consider an offer with a fin. reward.

Answer 1

Apply API discount.