You can tell if your flavor entry is correct but how many other recipes use the flavor. If you're the only one either you're from the future or it's misspelled.
Like Killer Custard, Extreme Sweet was renamed prior to release but some companies are still using the original names. I've merged them so many times that I don't bother anymore.
Well...I'm in Brazil.. so both are kind of new to me here kkkkk I've got both of them, and used the extreme in this recipe. They don't look the same color though, extreme being transparent and extra a little yellow'ish...