The FSS system counts down to the next servicing in two ways. It is either in days or miles. When the system is in the "miles" mode, the number is always rounded out to hundreds of miles, such as 6,500 or 400. Being that your display says -281, I'm sure yours is currently measuring in "days", meaning you are 281 days past due for maintenance. Mine was -59 when I first got it. You should notice the number increasing by 1 each day.