I am curious on the effect of the Bulzeye optical scope boosters. How much actual boost do you get from these? I see they offer what they call 3X, 3.5X and 4X. I can't believe a 3X placed on a 24 power scope will actually result in a 72 power equivalent scope. Are these number additive, ie. resulting in a 27 power scope on a 39 x if placed on a 36 power scope?