i put it in tow/haul the second run
This is very puzzling to me?
First off you will see different results on different days on different dynos. That's just the way it is.
Now,
Seems no one Knew how to properly dyno this vehicle,don't take offense. What gear was the final sweep measured in? Also the torque converter should have been locked either by locking it in in forth gear or if you did a sweep into overdrive ,sounds like that's what you did,then the torque convertor should have locked regardless if you were in tow haul or not! This is why it's so puzzling to me that you yielded a significant different number in tow haul.
Also sweeps done in 5th always yield a higher number. What you want is 4 th gear torque converter locked.