Recertifying nitrous bottles?

Finally got past the holidays, a recurrence of my ulcer, AND a root canal! So yesterday afternoon... drove 40 miles to the shop who'd underfilled my nitrous bottles. Actually to his home/garage where he keeps the mother bottle. Turns out he's a well-known racer on one of the Street Outlaws TV shows.

He tried to blow even more smoke up my *** that "once you crack the valve [which I hadn't] you can easily lose three pounds", bottles are full at 24 lbs (clearly marked 24 lb, 12 oz on the labels by NOS), and his scale was in metric because "Nitrous is always sold that way". In 40 years of wrench turning I've never heard it in anything but pounds.:rolleyes:

Anyway I got 3 lb added to the bottle with 7 lb in it. I hope. Feels the same as the other one now. The other one is only about 1/2 lb short, and I hadn't had room in the freezer for both (he won't even use a pump, just freeze the receiver bottle) so he wouldn't top it off.

Claims he's been selling nitrous since 1993. I wonder how many have been shorted besides me... Anyway I know who NOT to do business with again. I wouldn't buy a glass of water from this guy if my hair was on fire. My ulcer doesn't want me to think about this any more.