Probably - but previously it had been the other way round...back in the 70's when the 'golden bowler' schemes were happening - my unit was short of corporals because of the 'knock on' promotions and I as a relatively inexperienced J/T was given an 'oversigning chit' to countersign maintenance documents - a few years later I would have been made an acting cpl to fill the slot !
At the same time we lost two top class trade managers through the 2 schemes -their subsequent replacements were nowhere near the same calibre (on that particular unit).
In those days it was 3 years j/t to cpl and then 4 or 5 years (?) to sgt for riggers and sooties.