This will be my first labv. Im looking forword to navigating with a roll chart for the first time. my question is the odometer on my 990 is not resetable by tenths. So if at any point I get off course there will be no way of getting my mileage and the roll chart to line up again?. Is this going to be a problem? I would really like to fallow the roll chart insted of following the yellow brick road on the gps.