I'm curious about the HVAC as well. In Rhode Island, and with a 100 amp owner's service, I'd assume that the central heat is gas. In New England, that usually means a hot water boiler. Then, that type of heating system is hard to accomplish in modular construction. What about A/C? I know that it is still common to build new construction in New England without air conditioning, but that's not quite as common as it used to be.
Could the reason for the 200A services to each unit be due to the fact that each one will have it's own heating system furnished and installed locally? If it is intended to be a heat pump with electric backup, the service sizes might make a little more sense.
Sorry to be providing more questions than answers. Something just seems to be missing.
"But the guy at Home Depot said it would work."