Found out my $9 scale was shorting me on postage, and I caught it by accident
I was packing orders in my garage here in Boise and my $9 kitchen scale from Target kept reading everything about 0.4 oz light. Didn't think much of it until I compared it against the certified scale at the UPS counter and the clerk showed me I'd been underpaying on about 30 packages. Turns out USPS catches that stuff and bills the difference back to your account, and mine was sitting at $47 in postage due. I grabbed a $22 digital scale off Amazon that's accurate to 0.1 oz and the difference is night and day. Anyone else get hit with those billing adjustments after shipping for a while without knowing?
Wanted to point out one thing that's a bit off, USPS doesn't actually bill the difference back for underpaid postage on regular packages you drop off. What really happens is the scale at the counter weighs it, and if it's over what you paid, they either charge the buyer or return it to sender. The $47 in postage due you saw was probably from your own shipping software account, like Pirate Ship or Stamps.com, not USPS billing you directly. Those platforms do audits and will pull from your account balance if the weight you entered doesn't match what gets scanned. Same end result for your wallet, just a different middleman taking the money. Still sucks either way, and yeah, a cheap kitchen scale is a trap a lot of people fall into without knowing.