Thank you, MD. I am searching information about this mater and cannot find any cutaway scope view or drawing comparing in detail this point in variable vs. fixed rifle scopes.
Thinking about this, my reasoning is: the only difference would be the movement of the erector lenses between them in the variable to change magnification (and the other coaxial tube and parts needed to do this, of course). Cannot see the need for more lenses than in the fixed power scope as this also need erector lenses. Am I missing something...?

Thank you for your help, again!

PH