Does the formula used by the DIC oil life index change when I use the tow/haul mode? Or should I factor in the miles I pull the trailer and knock off points from the remaining oil life number?

Thanks,

It doesn't matter what mode you are in, the counter still ticks away.

Tow/haul would change the algorithm, but I doubt you would really notice unless you drove for thousands of miles in tow/haul. The oil life monitor uses run time, rpm, vehicle speed and engine coolant temperature as inputs.