is that the 1/16" back and forth movement of the hook also allows for accurate measurement of inside surfaces. When the hook is extended (adding the 1/16 to the first inch) you get an accurate measurement when you hook the tape on the edge of the work piece. When you press the hook end into the work to perform an inside measurement the 1/16" is the thickness of the hook, with the gap eliminated.

People always say "oh look at get old timey ruler." No, it's brand new and great for making exact inside measurements with the little slide extension.

My boyfriend bought me a laser measuring tool last year for Christmas. I thought it was a gimmick and scoffed at it but the thing is dead on up to 50 ft.