I have to say .. I have shipped to the Canadian Guys and never had and issue ..I have also shipped large packages to canada and Europe and also never had an issue. I;m very sorry to say ..never used FEDEX ..they are EFFICENT LOONATICS ... I use USPS all the time. I just had a set of seats shipped from Michagan and thye arrived very quick to Post Man was pissed he had to carry them to the porch.
My personal opinion in the DUTY or TAX is the end users responsibilty .. I could be wrong but I thought that was the unwritten rule ??