I think the answer really depends on what it is you feel velocity impacts. Obviously, it impacts power factor, but other than that, it may impact recoil, gun cycling reliability and consistency, and accuracy. So, to the degree you feel these factors are a) impacted by velocity to some significant degree, important, and c) controllable...that's the degree to which the variation is acceptable.Another way to look at it is, what can you do about it and what level of effort does it take?
I appreciate all the info. I was not worried about power factor (I am well above that), but was getting a deviation of up to 30 fps and was wondering if that was extreme. I'm glad to know it isn't. It has no significant impact on felt recoil or dot movement.