My Weaver Tactical has a locking turret that has to be pulled on to unlock and adjust elevation/windage. There is a little play in this feature and because of that, counting the lines that indicate the rev is a challenge which is why I prefer to KNOW how many revs from scope bottom to my zero. My DMR is less sloppy, but I apply the same practice with it.He should know which revolution his zero is on. They are marked for a reason.
A friend at our club has the same DMR. He was invited back to the 1100/1200 yard range (can go as someone else's guest a limited number of time before paying for this upgrade) and he was lost in his revs. Ended up with a low impact that luckily skipped into a back stop. He immediately was talking about scopes with zero stops.
Again, you certainly can get a lot of good use out of a scope without zero stop, but extra steps and care need to be taken.