Trijicon has the sub tension at different powers below the reticle . Says .5 mil @15, is it simple enough to deduct 1 [email protected]? Just wanted to see if I am missing something, seems too easy.

If the word you meant to use was " deduce", then yes I think it is that simple. If the mark is .5 mils at 15 power, it would be 1 mil at 7.5 power.

You got it figured right.