I really don't get this "bad habits" thing.
So a CPL with over 250 hours will have picked many bad habits to make him not attractive to the airline. The same guy becomes a FI, with 1500 hours and now he's attractive and hasn't got any bad habits ?
If someone's been through 250 hours, a CPL test (which I believe is carried out to the same standard whether you are ab initio, or modular or training with the local farm strip
) sure he's reached the standard excpected by the CAA examiner, and would assume he's equally qualified as someone who started flying last week and has done an intensive ab initio course !
The bad habits thing is probably an excuse to cut the modular students out and keep monopoly between airlines and certain flying schools.