Max SAN is the limit allowed by the rules: 7. It's all a matter of priorities on how you want to spend your CPP. Just as easily as you can buy it, your opponent could knock that value down during the course of the scenario.Could have been more specific, I only had the scenario name in the subject line.
Anyway, it was for the OS-17 scenario and the name is "The Worst Place of Any", it is from Objective Schmidt and is a 25 turn scenario (mini-CG).
Both Americans and Germans can buy SAN+1 multiple times in the scenario but to me it seems weird that it is possible to buy SAN to the highest level in this scenario as it is quite a rural map and those scenarios tend to not have that high SAN.