It looks like two different things are going on. The software is scaling the z value (10 %) and rounding the Z value to the nearest thousandths of an inch . Your 1.80 mm depth X .1 = .180mm, should be 0.007086 in.,
but .007 in = .1778 mm exactly.
I'm not familiar with this software, but I'd go through the settings to find a scaling factor.