hmmm... Without testing it. I think I understand and it's not as helpful as I had hoped.
After each stop I can adjust my mileage by 10ths to correctly read the total that is on my roll chart. If I get lost, this does not help. The more distance between stops the more my OD will be off and the more chance I have of missing a turn and I can't correct for that until I find the correct stop the correlates to my roll chart.
I guess it's better then being off accumulate every stop, but it would just be easier to have an accurate OD and not worry about it, like using a speedhealer or like.
*found my handbook
Anyway, I made my own chart (minus the roll I haven't bought yet) and wanted to try it out tomorrow on a ride I have planned.