Anyway an E-grade like system for bouldering would nicely show the difference between say, Gritstone Megamix and Mermaid that 7A and 7A does not.
If you were bothered about that you could just add a ! like eg. the North Wales Bouldering guide does. Its also fairly obvious from a simple look at the problems in question which one is highand which one isn't.
Anyone using font grades that way hasn't thought about whether it makes sense even remotely and they're using them wrong. Its as simple as that.