oh no I know that. I've just never, EVER seen one on a lower-level horse, and I guess that the reason for it is probably that it's not as strenuous. Monty doesn't really need something like that (he has HUGE open nostrils, it's the arab in him, and he can go at a gallop all day with crazy fast recovery) but that said we're not competing at a high level at the moment (my confidence is the problem there) so his natural efficiency is more than enough.
By the way our E grade is like... 18 inches? Tiny stuff. Monty doesn't respect it at all and just barrels through it because he's a B grade eventer, which is obviously a lot bigger. I can't remember the exact heights and spread widths but I can find them out. Biggest solid jump I've jumped was C grade height, 85cm high (just under 3') and 1m wide (which is about 3'4"). I'm training over 3' showjumping style fences at home.
I don't know your levels at all :\