All the way down, all the way up (to straight arms), they DO NOT tolerate any short cuts - punished by two counts deducted if you allow your body to bend or not perform the full range. A couple in my syndicate couldn't do this - DROP AND GIVE ME SIXTY!!
That is not strictly true regarding elbows in all the way. They are normal press ups (not tricep push ups) with the range of movement going from straight arm to chest all the way down. Providing your arms reach that 90 degree mark, that will count as a push up.
Granted, I am not talking from personal experience but my sister's husband and my brother have both passed AOSB and they both have said the same thing.
If you wanted to, you could theoretically do all of your press-ups individually with a rest between them. Remember though that lifting yourself off of the floor is much harder than doing a press-up though.
For sit ups I can do about 60 in two minutes; but I've been trying to get the form rather than the numbers. Press-up wise, after realising I wasn't going deep enough, I can manage 20-25ish. I have plenty of time to improve though.
I've also heard that they secretly film the dinner on the final night too... tbh, if they actually cared that much who was the best at the PFT, then they wouldn't stop it when you got to the required standard.