Store name https://pillowflex.3dcartstores.com/

Our shipping calculator is calculating shipping rates wrong if 3 or more items are purchased. For example if you add 1 item to the cart the shipping calculator on step 3 of checkout will give a price of the correctly calculated shipping amount from fedex and it will match the rates from fedex.com . If you add a 2nd package it will give the correct amount also but if you add a 3 or more it will give a completely wrong shipping amount. For this example my shipment is going to VA 23220 one package is $22.23, 2 is 44.46, but the 3rd is $133.38, it should be $66.69 according to fedex.com. It doesn’t matter if I use fedex list rates or the discounts associated with my account I am getting an error of about the same amount.

My shipping settings are as follows
Each of my wholesale products weight 42lbs each and each ships by itself.
In shipping settings I have Max Box Weight set to 42lbs
In shipping methods I have both fedex ground and Home delivery set to All customer groups and min weight 1 and max weight 1000

Does anyone see anything wrong with this please let me know.