As I understand it, while the AAS has won the auction for Sky & Telescope, they have not yet officially taken over ownership. F+W Media is still the owner for the moment. However, I think it's likely that the AAS will take over soon.
That's probably true. No doubt there will be some blips when the ownership transfer actually takes place -- such as in the details in online ordering. There certainly were at the last change of ownership.
Personally, I am reluctant to buy anything new from S&T until it's clear that the transfer has taken place. I would hate to give my money to F+W rather than the AAS!
The PSA and JPSA strikes me as some of S&T's more popular products. I would be surprised if they throttled an in-progress revision of the atlas.
As I understand it, both Roger Sinnott and Gregg Dinderman, the driving forces behind the PSA and JPSA, are enthusiastic about producing new editions. And it's hard to imagine the AAS not agreeing, since it would obviously make good business sense.
To put things in the least flattering light, upgrades are how companies make more money off existing products. To put things in a more flattering light, Roger and Gregg are constitutionally incapable of trying to pass off dross as gold. Whatever changes are made, I'm sure they will enhance the value of the atlases significantly.
If I were in charge, I could easily specify a half dozen detailed charts that would be extremely helpful in some of the more crowded regions of the sky. And I know from past experience that anything I can do, Roger can do better.