Exactly true. If you have figured out what kind of boost you can run through a given engine with XX octane fuel, then you always aim to keep the boost at or near that level.

There is always a maximum boost level for a given nominal CR of a motor + quality of fuel.

So less boost isn't bad. Even if you made the SAME power, what you'd want to do is turn around and pulley the compressor to gain back the lost boost... and you'd pick up more power, without hurting the motor (given you're not past its design limits in terms of power).

So it can be a win-win. Gain a little power by adding the mod itself, and then pulley the blower back up to gain the lost boost. **The issue can then be if your current blower is efficient enough to spin it faster. **