Ok question: If I don't plan to move the scope from 7x while shooting at longer range, what would be the reason behind testing POI when changing magnification?

I can fully understand running the CDS to check the erector system (box text I assume?). How does changing up the magnification on a variable power if I don't plan to shoot long range with any less than the upper magnification?

Have the feeling I'm behind the curve on some of this. Willing to learn.

As a secondary question: Why no love for the Mil Dot? It seems like a great way to "gain" elevation in a scope with limited travel in the erector system. Again - am I behind the learning curve on this? Take a one inch tube scope, add a Mil Dot, and it seems like a great combo to keep a rifle light AND have the tools to stretch it for fun. Can use a combo of Mils in the reticle and clicks in the erector to ring steel out long. Yes? No?