Yeah the GPS thing @hannah_craig mentioned is so true, tools just have their own weird ways. I mean my old car's GPS would always try to take me down this one closed road, every single time. It's like it had a favorite path even if it was wrong. I guess meters can be the same, they just settle into their own little idea of what the right number is. You gotta stick with the one you know, even if it's a bit off.