This question came to me as I've been asked to wire a new house being built with electric heat. A 100A service was specified.
This is the first time in my life I've been asked to supply a 100A service for a new house and electric baseboard heaters.
So I did a load calculation and came up with 85A.
I always thought that the max. calculated load for a 100A service was 80A and the max. for 200A was 160A.
I'm wondering if this is a case where I was originally taught wrong and never questioned it, or if something changed and I never noticed because everybody asks for a 200A service.