I don't reckon it's a small leak. It holds for about a month from what I can tell. I just had it recharged last month. 2 lbs worth. Hmm.. these guys charge 60 per hour. So at your estimate, with the 10% discount, it should hover around.. $360 labor + $330 parts= $690 != $1800. Ugh.
I have a mechanic friend that could do this and I can get the parts at discount. I think that might be worth a proper shot.
I'm a computer guy, so while I was quite comfortable replacing a ROM chip on the ECU, I'm not so sure about doing compressed gas lines for the first time on my bmw. Thanks for the kick in the right direction Bill and Bob.