EE may even require 200% neutral because of harmonics currents generated by the VFRs, UPSs, electronic ballasts and other switched power supplies that comprise the bulk of building loads these days.
Very very very few cases where anything less than 100% neutral would be acceptable. And generally cheaper for the customer for the EC to just pull a 100% neutral it than spend the man-hours for the engineer to calculate the minimum safe size. Though, if there are extenuating circumstances- like the existing 2-miles worth of duct bank will only fit a 50% neutral- I'm sure the engineer can be obliged to break out the modelling software or throw an extra relay into the switchgear
