Hey folks,
Here's the update -- Got a different tech this time, a much more confident one who obviously had a ton more experience. Really nice guy. He immediately made me feel more confident about things.
He looked over the entire system in detail then we went out back, where the outdoor unit (compressor is it?) was making a horrible noise. He hooked up his gagues to realize the system had been LOADED with R22. Like WAY overloaded. The gague was going through the roof. So he let me know I'd be refunded everything except the original service charge to come out, and no charges at all for today. Completely sucked the system dry and then refilled with the proper amount of R22 for the system.
He said he didn't actually detect any leaks, or think the system even had any, and didn't see any reason why it would have iced up. So I'll be keeping a close eye on it the next few days. He did show me that my inside coil was pretty corroded from 8 years of usage. Also, my outside unit is not in the best of shape either, efficiency-wise. A very stupid person (read: me) tried to clean it 2 years ago with a pressure washer. I got about halfway done before I realized I was pinching the fins closed. So the unit has been working very hard but has cooled well for the past 2 years. I realize its days are numbered.
In the end, he admitted that the last tech made a lot of mistakes, the key being not letting the coil defrost before service -- He didn't say anything about mixing coolants, or the dye, but he DID say that he needed to let the coils inside defrost before hooking up the machine to get the coolant reading -- He didn't. Hence the reason he was able to extremely overfill the system. I asked if this could have damaged anything and his reply was no. I imagine if I want to be a really squeaky wheel about it I could complain and get free service or parts, but the guy was nice and spent a good 3 hours with the system and I at least have had a good checkup on it and new R22. We'll see how cool the house gets tonight, of course.
They did quote me a bit over $4k installed for an entire new system from Trane - Or something like $330 for a full cleaning of the system, inside and out. I didn't accept either. Think I'll still go with another company (or at least get another estimate) before replacing anything, parts-wise or system-wise. The GOOD news of all this is at least I am not out close to $600, and can go back to square one as far as finding a good contractor to ultimately fix whatever the problem is.
What a day.