This module allows an order total to be adjusted based on the payment method chosen by the customer.
"Module compiled by Ryan from a schnazzy patch by cYu."
After enabling the uc_pma module you will be able to go to Administer->Store Administration->Configuration->Payment Settings->Payment Methods in order to set up these payment adjustments. Adjustment fields will be added to your form where you can specify a flat amount or percentage to be added or subtracted from an order that uses the associated payment method.
These fees and discounts will then be displayed to the customer during the checkout process with small print underneath the payment method which summarizes the adjustment.
One important note is that a percentage fee applies only to the sub-total. So if you've setup a 15% Check fee, you could have the following cart (assuming a $10 product, a 10% sales tax, and $4 flat rate shipping).
$ 1.00 Sales Tax
$ 4.00 Flat Rate Shipping
$ 1.50 Check Fee