What kelvin are the bulbs? This sometimes plays a role in coral colouration.
I think the reccessed poylps are just due to the really strong 400w lighting. Montipora Digitata aren't light demanding SPS corals. Also the poylps retract a bit if it's put under really stong current, in my experience.
A lot of factors play a part in coral pigmentation, every tank is different. Both corals sound healthy though.
HTH a bit.
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