747, whist not disagreeing that even recruits might qualify for the X-factor, the precedent for removing the X-factor from recruits or at least scaling it back is in FIP.
Flying Intructional Pay was first scaled back and then stopped in the late 80s on the grounds that the guys (before dolls) wanted to fly and did not need the inducement of FIP.
Therefore we could conclude that the recruit wnats to join and thus does not need an X-factor inducement.
If the X-factor was graded and reduced under certain circumstance then more dosh could be spread where it does most good. I am not advocating X-factor for FS X cause he is in a deployable job and no X factor for FS Y cause he is in a non-deployable job. Both would get it because in themselves they are both deployable. FS X would have his scaled back if he were unfit or declined to be deployed. A small difference. Similarly Y would also have his reduced if his MES was lowered.