The technical specification of the tilt measurement accuracy of the RTC360 is 180 arcseconds single standard deviation. That means that 3 of 1000 tilt readings can be 9 arcminutes off the plumb line. Comparing 2 stations with each other, one may find 18 arcminutes difference. This is about a third of one degree.

The image shows two lines intersecting with a 0.3 degrees angle.

This angle of intersection is small and within the range of the technical specifications of the RTC360, but it is well visible for the human eye. If measurements of an RTC360 do not seem upright or tilted against each other, a sophisticated investigation needs to be performed to understand if there is really an accuracy problem or the observed phenomenons are dedicated to the measurement scene and the technical properties of the scanner.