I am trying to find out the maximum angle that the tweeter on the invite 525 ceiling mount can be adjusted.

I have a vaulted ceiling that slopes away from the listening area. The slope on the ceiling is about 30 degrees. So I would need to adjust the tweeter so that it corrects for the 30 degrees and then points about 40 - 45 degrees the other direction. All total I am probably looking at 60 - 75 degrees total correction to point back to the listening area. Can the tweeter be adjusted that far? How much difference will it make if it gets within 20 degrees of the listener?

Nope, it won't go that far (only tilts about 10 degrees). Besides, you'd really need to point the entire speaker for that much of an angle.