I have no idea where you started or what the groups looked like getting there. But if your not experiencing heavy bolt lift, or any other physical sign of to much pressure, I would never stop going up! Smokeless powder, especially the slower powders have never burned even at low pressure, the more pressure in my experience, the more even the burn, and the better the results!
200 yards is not far enough take great notice in minor velocity spreads, but at 70 or more fps it would show part of your vertical, one more reason I don't work up loads without a chronograph, but it does show me when powder is burning more even.
But even with what your getting, I would first replace the scope and check my bases and rings making sure everything is right and tight. I can't count the times, I've seen scopes that were dead nut when they were last shot, and outa the gate after sitting some time, WTF.
But if that checks out the same,,, take it up, 3 shot groups,,, .3 grain at a time, I've got guns that like 1.5-2 grains or more over what a book said was max, and then I've had guns in the same caliber that showed book loads before max were getting to hot! just part of load development!