Most injectors have a min and max pressure, they also have a recommended pressure that they should be set at to get the listed ???cc. Raising the fuel pressure beyond that point has a negative effect on the injector and spray pattern and hurts the injector. I would never (from a tuning stand point) raise the fuel pressure to compensate for "keeping AFR in check", that's what the ecu is for. A RRFPR is an old school way of doing things that's not very reliable and needs to be checked constantly. If your tune in MS is correct you should be able to run as high of a boost pressure that you want, until you run out of injector flow capacity.
If you are out of injector flow capacity and are set at the factory pressure, sure, bump it up till you hit the max recommended pressure. Just adjust the entire map to compensate for the change, and expect a low injector life. My 2 cents