Lessons to be learned about shipping USPS

I need to learn that shippers trick, Cause I ,as the shipper always get the ding.
I shipped a pair of bucket seats to Cali for $100 . Then about a week later UPS dings me for $92 . That was a loss !
But really, don't know why they dinged you, maybe the guy didn't have an account set up. I have shipped in those tri tubes and never gotten dined. Your just LUCKY I guess !:poke: