This might not be the right forum but.....Does the sensor that tells when to change your motor oil change when you run a different oil than what the truck came with ? I changed the oil at 5000 mil...
The algorithm takes the type of driving into account. Short trips mean shorter oil life as it doesn't get hot enough to burn off pollutants. Long highway trips are much easier on the oil. With towing, I assume any too hot conditions might shorten oil life, but typically not stop and go, so not that bad. With my truck, the default is about 10K miles, but I reset it to 70% which would warn me at about 7000 miles.