This setting affects the cost of the booking according to the payment gateway used. Specify a percentage or fixed amount. Use minus ("-") sign for decrease/discount."
How does this show up for the customer, is it after the customer selects the payment gateway or before? Lets say you have two payment options, Stripe and PayPal. If we increase the price for PayPal booking, and the customer selects PayPal, the total cost will increase after he selects PayPal. Can't this turn out as a turn off to go ahead with the payment when a customer sees additional payment. And confusing if he next time choose Stripe where there would be no increase in the booking.