If you decide to apply a surcharge yourself, you will need to determine an appropriate surcharge that is equal to the cost of processing payments. Failure to comply could result in excessive surcharge penalties. At the end of the month, you will still receive a bill for transaction fees if you choose to use a merchant-controlled surcharge. In order to cover this bill, you must ensure that you have collected enough surcharge fees. Moreover, the surcharge may need to be split off from your sales, which may require additional administrative work. SmartCharge’s simple Flat Rate add-on, however, allows you to choose whether or not to add a merchant-controlled surcharge.