The main reason is that the platform will deduct the platform commission before settle the balance to you. For example, the commission rate of the platform is 15%, your service price is $100, and then the amount you receive will be $85 (100-100*15%).
If there are promotion available on your online shop, for example, a Voucher of $10, then the amount actually paid by the customer will be $90, and the final amount you receive will be $76.5 (90-90*15%). If the Voucher is issued by the platform, this part of the cost will be borne by the platform.
