For me I feel like the pace at which I pull back the RAS is what controls the pace (amongst other things)...
The Forward push determines line and the timing of the forward push also determines if it is a "good" delivery (and therefore at an optimum pace)
The timing of your release when you push R stick up has no effect on the speed of the delivery unless you miss the whole green part all together, then your pace will drop significantly. RS UP is only for line and length
Max said his problem was pitching the ball up
If you select 'good length' deliveries and time your release on 'good pitch' every time, majority of your deliveries will go slightly over the stumps.
Instead of timing your release for 'good/ideal pitch' push R stick a tinny bit earlier for the 'full pitch' zone and you will hit that perfect length right on the bails of the stumps.
You will not lose any pace because it's an extremely subtle change in pitch length but you are still in the green zone.