The house is obscene, but just because one has 400A service doesn't necessarily mean they're being inefficient in doing so.
It could just be to handle momentary bursts, and the equipment drawing that power might actually be doing the job more efficiently than something that does it slower, drawing more power cumulatively over a longer period of time.
It could just be to handle momentary bursts, and the equipment drawing that power might actually be doing the job more efficiently than something that does it slower, drawing more power cumulatively over a longer period of time.