I use the meter to get close and as a tool to get the curve flat all the way down the track. Ticket/mph is the final tune. Once you are base lined and the curve is flat you can then go up/down depending on DA.
My understanding is that once the engine is at the maximum load, the best fuel mixture is pretty stable or flat.
I'm not saying that's always true - just my understanding.
Maybe with low gear ratios in drag racing sometimes that max load doesn't occur until near the top rpms/ end the strip?