It is not called a frontside overcrook because that name depreciates the difficulty of the trick, as the lock-in, which is essentially that of a backside crooked grind, is considerably easy. Instead it is called a fs nosegrind so that it is more distanced from the easier backside crooked grind.
On the flip side, calling a bs overcrook a bs nose grind undervalues the fact that it is locked in the same way as a frontside crooked grind, which is a notoriously difficult trick to lock into and balance.
It is the same reason noseblunts are called noseblunts, and not alley-oop noseslides. The logically inconsistent names serve to either mask the easiness or emphasize the difficulty of the more fundamental tricks that constitute fs nose grinds and bs over crooks.
This is how I see it, at least.