Not having the ability to talk with a live person is a drawback. Heck, they're probably from another country and I'll have trouble understanding what they say anyways.
Rocky, I signed up for the click n ship acct. Do you use this shipping label: PN: LUEBAYSLW10
Back to calculated shipping: I was checking out the free PM boxes and saw that flat-rate boxes are also offered.
That might be an advantage where someone orders a large number of heavy items that can fit in those boxes and the calculated shipping may end up being more.