A quick calc the way I see it
1100 sqft @ 3va 3300
kitchen/laundry 4500
7800
3000 @ 100% 3000
4800 @35% 1680 Gen Lighting 4680va
Gen lighting 4680
water heater 5000
stove 8000
MW 1000
DW 1000
18680 @ 230v 82 amps per apartment
4 apartments 328a
I believe there are some diversity breaks you get on a 4 plex but without looking, this is not far off before you add the "house" load.
It sure sounds like a 400a service to me, maybe more simply because you gave each owner 200a. They start thinking hot tub and stuff when they see that big empty panel.
