PS 400 command would be even better anyway.
I'm not a rotary pilot but the principle being presented was that the instructor actually has some experience before they start teaching. It's hardly going to be 250 hours of dual flying in those hours now, is it?
The 400 hours required for heli instructor has nothing to do with passing experience on to students.
Helicopters are unstable in all axes, and it's extremely easy to fatally damage a two-bladed rotor system with mis-handled controls. Without significant time on the controls, it's very possible that a new instructor would find themselves in an unrecoverable situation when they let new students fly. Add pattering into the mix, and watch things get interesting.
Conversely, most training aeroplanes are stable in all axes (up to a few degrees of roll), so the workload is quite manageable and the student's ability to kill you is fairly limited. Pattering while letting a trimmed aeroplane fly itself is not outrageously challenging.
While it is very important that instructors have skills & knowledge to pass on to students, let's be realistic about how much flight experience is needed to teach someone to fly straight & level. Bugger all.
(Yes, I am currently instructing on both)