In my Club we had three MPAGB's at one time and all had FRPS as well. I think you will find that most MPAGB's already have their FRPS. Whereas, you can use the same image at the different levels, it is not as helpful as it might seem. For an C level image to be of any use for D level, it would have to be exceptional. You certainly cannot just big bang PAGB. It took me 4 attempts over ten years before I succeeded in DPAGB and a fellow club member gave up after 4 attempts and he is a national level judge and has an MA and ARPS. However, I do agree that they are very different and require a different approach. I will not be attempting MPAGB myself as I know I do not reach such high levels.
I will watch Lindsay's progress with interest as I have not ruled out attempting ARPS sometime but put off by the lack of RPS events locally.
Dave