I was involved in a bicycle accident about 6 weeks ago which damaged the RD. I think the damage is mostly cosmetic, but a replacement was put on the estimate for a 10 speed Chorus. The mechanic said that it would be compatible with my 9 speed record levers.

The problem is that the RD would have been purchased in 1999 and Campy changed the pull ratio within the next year or two. I had to do some digging on online suppliers to come up with the levers I have now when I refurbished the bike. While the mechanic in general has my confidence, and I accept that later versions of 9 and 10 speed have the same pull ratio, I am less than confident that I can replace the damaged der with a newer model and maintain compatibility with the levers.
Looking for info on compatibility issues. He said he would work on the issue from his sided.