I change the oil within 1k miles of the maintenance light coming on. I did drive across country while towing a 30ft Toy Hauler without changing immediately. Maybe 7k miles.
The only reason I am inclined to add ceratec is because of the mileage. There are no oil leaks and never have to add oil between changes.
I use LM fuel additives and when those are not available I use BG44K about 3x a year.
so, the ceratec is more of a pre-maintentance thing in my understanding. Help to extend engine life and keep it running at optimum standards.
If im wrong, then I'll add it to my diesel tractor.