Edmund Allyou need to do is to look at the physical dimensions of it. How can the objective diameter be 60 mm when the outside diameter of the scope is only 55 mm??? Another thing to consider is that a 40X magnification would be almost useless to handhold. Any small movement/vibration would make the image very shaky. There's a reason high powered spotting scopes have a tripod mount.

Edmund Theapparent offset is probably because you have set it to measure from the back of the casing, and not the front where the tape comes out. A 3 second press on the button will switch between front and back benchmark.

Edmund Isearched for the M8, and it seems you got it wrong. It's the M8 that has that horizontal bar. The M5, this one, does not. That actually makes sense. M8 (higher number) has more features than the M5. :)