Purging on small pipe is dirt cheap compared to one failed X-ray, so I don't get the guys calling it a waste. A bottle of argon lasts forever on 2 inch and under, and the gas cost is nothing next to cutting out a weld and redoing it. Half inch tube is where I'll sometimes skip it, but anything carrying product or getting shot, that line stays put.

Wait, you paid her $1,200 and she found $4,600? That's like hiring someone to find your lost keys and they come back with a winning lottery ticket lol. I'm curious though, did the IRS letter actually spell out the penalty amount or was it one of those vague "you owe us money, figure it out" deals? Because I got one of those two years ago and it turned out to be a $75 late fee that felt like a personal attack. Sounds like your bookkeeper earned her keep plus some.