need some help

I need some help on the lower order fee function. I couldn't get the lower order fee work. The fee (for example $8.00) will show up during checkout page successfully. But when I pay it with credit card, the Low Order Fee was not charged. I searched many forums and found some suggestion. I didn't include $ or .00 in the set up. I sort the modules in order. It still didn't work. Modules Sort Order Low Order Fee 4 Shipping 2 Sub-Total 1 Tax 3 Total 5