Never before now has any leve required the use of mastercrafting books, so this has never been a problem. The whole idea of leves until now were that they were easily accessible ways to earn some experience, so gating it behind high-tier recipe books just seems silly, doubly so when it doesn't even inform you.
We have literally hundreds of recipes. If you're searching your entire recipe list for something which doesn't exist, it can be incredibly frustrating. Better to be upfront about this sort of thing rather than annoy and confuse players.