Sure you can do that. I prefer to have my front soundstage(L-C-R) with the same amplification and let my receiver power the surrounds. With your configuration, you have the left and right channels at 200w and your center and surrounds at no more than about 120w each. I know wattage doesn't mean everything, but having a seamless transition in the front soundstage is very important to most. Why not try (3) MA-700's L-C-R and have receiver handle surrounds.
Bill