Yes it's from the data I used some time ago.
The shooting efficiency is very different. If you take out the fouls, guarded shots are much worse than assisted shots. There is a huge component of shooting efficiency on guarded shots that comes from shooting fouls.
PA will definitely increase the amount of assisted shots, the question is how much? Shooting will also increase shooting efficiency outright, the question is by how much?
The issue you are trying to assess is: how much are marginal points in PA worth compared to marginal points in shooting and what is their cost? If you go from 13 to 14 PA, how many more assisted shots will you get and how much will it cost you in terms of salary? Conversely if you go from 16JS to 17JS or 13JR to 14JR or 16IS to 17 IS how will that impact your shooting efficiency and how much will it cost you?
Salary wise I'm pretty sure adding PA is cheaper. Efficiency-wise I'm not sure, especially for big men. I had a big man who had 1DR 1HA and 6PA, he was been super efficient for me as a C in D1 and he had more assist than turnovers. If he had 12 PA would he be shooting as much? Probably not.
Because inside shots are more efficient, logic would dictate that you put PA on the players you don't want to take the shots or that will take more inefficient shots. This is usually the guards and that's the way most people play this game. If you have elite guards like those 2 Aleksandar bought several seasons ago, then you may try to push PA on the other positions in order to get them more assisted attempts. However, whether this will work and what the cost of this would be I'm not sure. I know that those 2 had at least 76 JS/JR between them and very very high salary though (around 200k), so the price for this strategy is not low.