Assuming it is a second focal plane variable...
For aim points, keep all ranges the same and simply multiply the dot values by 3/4, ie 12x/16x.
For instance, if 50 yards was 2 mildots at 16x, it will be 1.5 mildots at 12x.
For ranging, is the scope true mildot at 10x or max mag?
Scott.