FedEx not calculating charges correctly

I am using Zencart v1.3.9h and Fed Ex module 1.4.5.2. When my customers purchase something they are given a quote for FedEx shipping. When I go ship the product by printing a label for the FedEx website I am given a second price and when my bill comes in from FedEx, it is for a third price. Usually the latter is the highest. When I call FedEx we establish that there is not problem in the wrong data being sent to them (i.e. wrong weight), but they say that the price on my website does not include the fuel surcharge. Really?? How can I get a consistent price from FedEx. Is anyone else having this problem? If I have to take $2 hit on every shipment with FedEx, I will just remove that option. Anyone have any ideas? :huh:

Does this follow any standard such as a specific percentage difference??

What did they have to say about the label price and their bill price??

Is there a handling fee that you can add in the shipping module configuration in the admin?