Not sure, but what I can tell you is that eye relief changes with the 2.5-8x throughout the power range about twice as much as the 2-7X does, IMO....
I have several of the 2.5-8 version. The eye relief does change with power, but it's largely a moot point for me. I mount the scope to be perfect on 8x, and at lower magnifications the eyebox is so flexible that I get a full sight picture right away anyway.
