Jack your question on poi at differant mag settings
If you dial in your elevation the poi will be the same on any mag
If when shooting the closer targets you decide to use your dots
you will have to use the same mag usualy the lowest.
The poi will be the same on the target but differant to your point
of referance on the ret.
To show this shoot a 10 yd target on full mag with your cross on a known point
and your elevation on zero check how many dots low your poi is now holding
your cross on the same point reduce the mag watching the poi move
Saying all that this wont happen if your is in the first/second focal plane can't at the moment
remember wich way round it is
but try the above if it doesn't move with the mag reduction forget every thing I just said