An interesting thing highlighted recently by
@radman is how tranny temps remain lower in Normal mode instead of ETC PWR. It would be interesting to understand if this could eek out more MPGs under towing.
I almost exclusively use ETC PWR when towing and haven't really compared. The lower temps suggest that normal mode is more aggressive to lockup the torque converter which makes sense. More lockup reduces temps, but it would also impact efficiency. IIRC, ETC PWR when not towing can make almost 1 MPG difference. And when towing, 1MPG is 10% more fuel efficiency which can be a big deal.
I do like the more aggressive throttle mapping of ETC PWR which is less effort when really heavy. It should hold gears out longer which again helps. When the TC is unlocked, is does create more dynamic gearing. All of which is helpful as designed. At the trade of efficiency.
It does make sense and perhaps understanding that can be an opportunity to eek out more MPG, if desired. Will have to give that a whirl next time.