Percent bonuses are added to the total cash out amount. Unfortunately, not all skins are covered by the bonuses (these are usually skins the commission on which has already been reduced). Therefore, the total sum that is written over the GET CASH button may not match with your calculations.
Unfortunately, we can't provide the list of skins which are not covered by the bonus program, for we are constantly trying to optimize it. In case you have questions about a certain skin, and you would like to find out whether you could get percent bonuses for its sale, please, contact our support team to get more specific information.