I know that when my alto neck was damaged, Beason straightened it out. He said that he brought it up to about the usual position, and it played OK, but not great, so he brought it up a bit more and said it was a lot better. I think the differences were small.
I guess that small bit of ovality can have an effect. Or not.
The double curve of a tenor neck has got to be more troublesome to restore, or to execute correctly in the first place.
In bending any tube there is always a certain degree of ovaling that occurs, no matter what the process, so that's another aspect to consider.
Honestly some of the neck stuff is hard to understand. I know that the 6M, one of the best alto saxophones ever made, frankly seems like it ought not to work at all, what with the distortions to the bore, right near the mouthpiece where everything is supposedly the most sensitive; and then there's basically no way that sliding sleeve is always leak tight either. Yet the thing plays wtih a great sound and almost perfect intonation.