XY Squaring Bug

2 things
I followed the setup instructions to square the XY
I moved 100mm X and 100mm Y and entered them in the appropriate boxes along with the Hypotenuse measurement. this returned "your machine is pretty square but you could move the right rail forward by 1.47mm. 1.47mm out over 100mm is not to my mind “pretty square”! Am I expecting too much?

  1. The results page also said that my steps per mm could be updated to improve accuracy, my XY measurements were exactly 100mm as commanded so I do not see how that could be true. hitting the update button, gsender says that the EEPROM will be updated to $100 x-steps will be updated to NaN
    same for Y on $101 so something not right here.