Re: cm and mil turrets
I think your question is badly stated.
If you are moving 4 clicks on a scope with <span style="font-style: italic">actual</span>, as opposed to nominal, 1/4 MOA clicks, then the POI will move 1 MOA, irrespective of what the scope magnification is. If you want to know how many clicks to adjust for a 0.5 mil change in point of impact, it's just less than 7 clicks, but the reticle specification is irrelevant.
If you're talking about the magnitude of the effect of making a 0.5 mil holdoff on a mil-graduated SFP reticle which is calibrated at 10X and used at 18X, it's 0.28 milliradians - assuming that the power ring is correctly calibrated and used. A 0.28 mil adjustment amounts to 0.98 MOA, so that would take just less than 4 clicks, if you were making the adjustment by dialing the scope rather than holding off.
I prefer FFP, too - I don't own any other kind of scope.