Fuji I think that owners of twins who fly on a PPL/IR would complain
A better way to separate it would be for a PPL/IR to have the abbreviated ground school (and a purely Class 2 medical, like is OK for the IMC Rating, with no pointless Class 1 add-ons), and for a CPL/IR or ATPL to do all the exams.
That would make sense relative to the proposed usage.