Ok, this is just an issue of the description of build area as 170 Ø or converting to a square. I see what you are talking about. Kind of a common problem when comparing delta printers to others, ideally software should adjust for that, when you tell it circular or square, but it does appear S3D may not be doing it correctly.
Enough thread hijacking, back to 0.7.5 issues. There are several already.
How are we supposed to use this Machine Radius setting?
Status Callback URL still broken.
Geometric Error correction, anyone have a clue what/how to adjust that?