Currently you have two shipping charge rules setup. The first one is checking if the total is greater than or equal to 75. If so then you are setting the shipping to be the amount of the existing shipping charge in the cart. This does not make a lot of sense to me. I think you should use a flat rate for the value of the shipping and enter an amount.
The other shipping rule is the standard USPS rule. It looks like it is charging you based on the quote that is returned.
Please explain exactly how you would like to charge for and not charge for the shipping based on these two rules. I will help give you some pointers on getting it setup correctly.
