Cutting Square object is inconsistent in length

Thank you for the links!

This is curious. The Vertical Cut isn’t so bad, but my Horizontal tolerances are very off. This is from the default ring system that was in the kit.

Measured Error

Vertical (left to right):
90.17 1.7
88.5825 -1.4175
89.8525 1.475

Horizontal (from top to bottom):
189.23 77
187.96 20.4
186.3725 36.275

Second question: How do I interpret the contents of the BedAccuracyTest spreadsheet?