Did you calibrate your tool length measuring switch? Usually, that line of code would set the tool offset using a number (in this case 0.
that corresponds to the offset of the switch from your spoilboard. So if your TLMS is 0.8" above the level of your spoilboard, then this offset would set your tool height to the exact level of your spoilboard. Calibrating the TLMS to the current spoilboard height should give you an exact measurement with your auto tool measures.