the cyclops is what provides magnification to the date window. it's the little bulbous thing inside of the crystal. what they are saying is that your cyclops is not centered about the date window. that will magnify the date improperly and make it look out of place.
date mag power simply means the level of magnification that the cyclops provides. is it 1x, 2x 2.5x, 3x etc
hope that clears it up a bit