I've got some large items in my store that are for that I can't ship and are customer pickup only. I set up my maximum package weight at 80lbs with tear at 0:0 and I mark the products in the catalog 100 lbs. Still, USPS comes up with $40-something shipping during the shipping estimator. Yet, if i add another product (totalling 200lbs) it works fine (no USPS shipping option.) Can't figure out where I'm going wrong! Is there another way to set this up?

Thanks in advance!