You do not have to put 10 hours in-game every week. From what has been explained to me by @ Winters is as long as you're getting desk work done, meaning doing tests and doing the IAs assigned to you (pretty much anything out of game), you do not really need to have 10 hours in-game. Now let's say you don't do any desk work but you like playing in-game, then yes, you'll need to put in 10 hours minimum. That being said, very few seniors only play in-game; the majority do desk work and put in a fair share of in-game time, which in that case is all good. There are a few people who are due to move up, and this will help identify the people who are over ArmA or are over being Senior APD, and that is okay, but they should give other people a chance to move up and achieve their goals.
I hope I made sense. I am willing to answer more questions, but realistically, this won't change very much and, in fact, will be very good for the people putting in the effort but cannot move up due to the lack of slots.