The distance is good but one of the dots around the green starting point is outside of the imprinted area, and two of the four dots that should be on the flat foam are outside, thus, slanting the scanning box.

The foot gauge is well centered, all three dots around the green starting point are in the imprinted area and all four dots that should be on the flat foam are corrects. The distance is good, confirmed by the green starting point. 

You can find a video tutoriel on how to scan a foam box here :