My truck toes (autocorrect lol)better with Shell VPower

On our last few long distance trips, I have noticed more power towing with our 2003 Yukon (6 liter) when using Shell VPower 93 octane. I have a bully dog tuner on the truck, set to the highest power setting which requires premium fuel. When traveling I used to fill up at any station that was convenient, I could fit into, and had a name that I recognized. Last year, we happened to fill up at shell stations a lot and I noticed that the trans was not downshifting as much on the highway over the minor hills. We just returned from a vacation from our home in Maine to Virginia and back. I tried to fill up at shell whenever possible in order to confirm, and when I filled with other brands there was definitely less power and the trans shifted to 3 on minor hills, where with shell it would stay in 4th.
I doubt I will convince anyone this is true, especially when shell 93 octane is the most expensive gas out there, just wanted to share what I have found.