Actually a lot of schools will return your fee if they get it before your AADSAS application. That's pretty likely to happen if you send it out when they say they send out your application (AADSAS runs notoriously slowly). If they return your fee then it just takes that much more time for you to get it in.
Just wait until you get something, the applicant pool is very large and it helps the schools process everything in a stream-lined fashion when you do everything on their terms.
Also, do you KNOW how easy it is to lose a single check that isn't attached to anything and shouldn't be there? 😱 Wait. 😀