I suspect that no matter how regulated the system is, the distances will still vary due to the difference in recoil.
Yeah, as far as I'm concerned if it a) reliably feeds pretty much whatever you throw at it without FTEs, etc., and let's enough gas escape so the bolt doesn't hit the back of the gun then the regulator has done it's job. Having mixed shells land in a small pile next to me doesn't really matter to me.