As a state school I believe the school is obliged to keep the same conditions for all candidates, so they should be those specified in the admissions documents. If you look at page 5 of this:http://www.kes.net/wp-content/uploads/2 ... n-Pack.pdf
It clarifies the entry criteria, which seem to be the ones you're quoting.
The official admissions document talks about the subject class sizes being taken into account before conditional offers are made so once you've got a conditional offer then it's simply (?!) a case of getting the correct grades. Further offers can be made after GCSE results come out, to those who didn't receive conditional offers. The relevant bit is on page 7 of this:http://www.kes.net/wp-content/uploads/2 ... y-2015.pdf
However, I'm only writing this as a parent, rather than an expert!