Our first motorhome was a 99 v10 pace arrow.
My primary complaint with it was it would downshift and rev like crazy at the sight of a hill on the distant horizon.
I bought this https://www.brazelsrv.com/ford-ultrapower-custom-programming
It was a new product at the time, and I had several phone calls with Jon Brazel regarding what I was looking for, and tried several tunes before I was happy with it. Jon emailed the tunes, and I connected the device to my computer with a usb cable to install the new tune in it.
Device is a handheld programmer that plugs into the ODB2 port. It uploads and saved your original tune, and then reflashes it's tune into your pcm.
The device can stay connected to read realtime info or be unplugged.
The difference was amazing. What I worked on with Jon was "no downshift unless I am at 3/4 throttle or more."
I got exactly that. I could force a downshift with my right foot, otherwise she would just stay in overdrive.
Additionally, there was a lot more midrange torque, she moved the coach much easier, pulled stronger, and was no where near as rev-happy unless I floorboarded the pedal.
I was very pleased with the product. It truly behaved like a completely different coach.