Jim,

You've gotten good at it so now you don't need to do it as much anymore. I'm glad to hear that you're staying cool without having to go into the shop and sweat to make it happen.

I agree that those last 100 Microns are not quite as necessary, but the more moisture you get out, the less corrosion that can take place from the combination of moisture and refrigerant. How much less, I wouldn't have a clue, but a deep vacuum is a good thing if you have the necessary equipment to make it happen. If not, and you can pull 28 inches, you're doing better than a few shops I've seen.