When I use the scrub method of adjusting on my leading, PS(win) unexpectedly jumps the number way up, even if I'm scrubbing left, even if i'm holding the alt key.
We have made many fixes to the behavior of transformed text and they are now available in the latest release, Photoshop 14.1, which you can download RIGHT NOW. I will acknowledge, there are still a few lingering issues to resolve, but for most users, these fixes should handle their problems. We felt it was better to get a partial fix out now than a perfect fix in the future. We are still planning additional improvements for a coming release.
If you are still struggling with problems, by all means let us know so we can make sure we address them.