I was weighing packages wrong for 2 years at my local counter
Turns out I always wrote the packed box weight on customs forms, not the actual parcel weight, and the clerk in Austin caught it when my package got returned for postage due. She showed me the scale reading on their screen versus my kitchen scale at home, and yeah, they weren't even close after tape and bubble wrap. Has anyone else been burned by trusting their own scale instead of just paying the extra 50 cents at the counter?