The distance will be the same regardless of what power setting you have it set on. Now with that said, a second focal plane scope made by any manufacture can have enough run out in the mechanism to be off some. There are some scopes, especially the cheaper models that when you shoot through the different power maginfications, the POI will wander. This is just inhererent with 2nd plane models.

I have Swarovski, Zeiss and US Optics with the reticle in the first focal plane and the POI will absolutely will not shift through power change. The reticle size increases as the magnification increases. Also, with the 1st or front focal plane reticle, your ranging abilities, be it mil dots, moa hashs etc will read correctly regardless of the power. The same cant be said with a 2nd FP. It's just the nature of the beast.