Why wouldn't they test before the deadline? At £200 a per person, it's in their interest as a business to have as many people assessed as possible.
They're obviously offering anyone who meets the basic minimum requirements the opportunity to sit the tests. If thats 300 people, then so be it. If it's a 1000 great, it's more money in the coffers.
However, it is strange that one school is doing it this way and the other two aren't.