OMG I have been on this merry go round with UPS & Fed X for 2 yrs now !! At work our standard box we ship is 50# 18x18x26 and just makes it dimensionally,,but if the box bulges ever so slightly be it the top or sides DING ...$6 more. "I'm sorry Sir this is all done with lasers to assure exact measurements". All the freight companies go by dimensional now, UPS started this crap as a way to make more money. We are lucky in Ohio now to have Pitt Ohio ground,they don't care..50# is 50#'s to them plus their rates are 35% below UPS. UPS use to have to send a second truck to pick up all the packages we shipped in a day....now they're lucky if they get 10 a week.
Fed X is so bad ( commercial business wise) they can't even give a rate chart,,they don't know what they're gonna charge you till its on its way!