Vantage going East is the easy side (one short steeper stretch but less average climb).. looking forward to the return trip results.
You observations on the ECM/PCM fuel curve are odd, mainly because that generation of diesel does not have any method of monitoring airflow. No mass airflow sensor means no fuel calibration based on airflow changes. The engine honestly doesn't "know" you changed anything.
The changes you noticed are most likely from the improved compressor wheel and turbine housing. Banks still calls it a quick spool housing but it is in fact a slightly larger housing than your stock one. The larger housing is why you probably felt sluggish when the motor wasn't fully warm but felt good under constant load. The drop in boost at cruise is also an indicator of the larger housing, but the drop in EGT's at the same time means the compressor wheel is more efficient across the board.
The additional speed up the grades is a great byproduct. The engine is going to fuel the same it did pre-modification you are just getting more power to the wheels thanks to the airflow improvements. A larger turbine housing means the air is exhausted easier on the exhaust stroke and that means less power is robbed in the exhaust stroke. The better compressor means cooler air in ingested on the intake stroke and cooler air means more 02 per intake stroke which means cooler and more efficient combustion.
I would not be surprised at all if it takes 30 minutes to come alive nearly every time you tow/haul. Less boost and higher EGTs are directly related to the larger turbine. As a turbine gets up to operating temperature it becomes more efficient, as you saw. If you want to help increase the warmup time I would consider a turbine blanket if there is room.
All in all it sounds like a great mod for the way you use your truck!!!
What is your GCW? Just out of curiosity.
