When working for Turners in Culver City many moons ago (the 80's), we found that most low and mid range optics change POA when changing powers.

The best thing to do is sight in at the highest power as that is where a shift in POA would be the most critical.

We found this out when a special optical machine was brought in that measured POA changes. We tested the scopes to see what happened when power was changed. The crosshairs would wander around the grid as the powers went from low to high and back.

The worse back then was Bushnell and I think Weaver.

Most of the really high end scopes were very consistent and had the least change or no change at all.

The best were: Ziess, Kahles, Swarovski, Schmidt and Bender, and Hensholdt.

Middle of the pact were Leupold and I believe Redfield.

Nikon was not making scopes then or at least we didn't carry them.