switched to 89 octane for my 2004 dodge RAM 2500

Most of the time I run the 87 octane in my Ram 2500. I have all of my trips planned out until October, so about one fill up before I go camping, I'll put in 89 octane and run 89 octane when towing. The computer will attempt to delay the timing with 87 octane to eliminate spark knock. That results in a lack of power when you need it the most.