No Import Duty Fee?

Seems like Customs messed up. I really doubt UPS paid it for you. When I ordered two P35s at one time it was enough to trigger the custom fee and UPS asked for it before shipping the rifles from the point of entry to the U.S.. When I bought one, nobody asked for the fee and I didn't pay one. Each P35 was a little over $400.
Tracking showed a glitch at Customs, a slight delay, paid Duty Fees on my other AGTs from Krales, this one just showed up. Gladly pay, if they catch the mess up but I'm not chasing them down. WM