Well this was a false memory I may now remember as false. No, it wasn't tenths. I think more likely it had to do with the claw at the start of the tape for att

Well this was a false memory I may now remember as false. No, it wasn't tenths. I think more likely it had to do with the claw at the start of the tape for attaching to your starting point, which does not stay at a rigid 90 degrees. My memory is that over several tens of feet I was off by 1/8 inch.