Hello,
Have you found an answer to how this is occurring? I’m currently experiencing the same issues. I ship with the FedEx pack rate but I don’t use the actual mailers. I was informed by a FedEx Rep that as long as the dimensions of my package were equal or less than the size and weight of the FedEx Pak rate, it would be identified as a FedEx Pak.
For most of my packages, I’ve been invoiced for the correct amount but have been finding some random ones where I’m being charged more (for example, I usually pay $11 but now being charged up to $14). Not sure how that is happening when my packages meet the criteria most of the time and then for some reason, some others don’t? Would appreciate some guidance ! Thank you!