Hi Paul,
I would think that most members here do precisely as you suggest (freeze curries). I know I do, and I agree that doctoring a frozen curry (in a way similar to the way you describe) often gives great results.
However, I also doubt very much that many BIRs (if any) do this as standard practice. I think they hit the nail on the head the first time around, without freezing anything.
But freezing them is definitely expedient for most home curry cooks.