Taking it in for a Dyno test

I'm taking the beast into Moutain West in SLC htis week for a dyno test.

I'm unable to find any obvious issues on inspection. No noticeable air leaks-(that's after i replaced two O rings on the cold sode of turbo a2a connector)

It continues to really struggle even mty maintaining speed on even the smallest upgrades(think overpasses). I'm not burning oil, no coolant loss, overhead done 3 months ago, egr#1 replaced 45 days ago, and I've got no codes. Mtn West charges $250. The benefit is, they can hook the Volvo diagnostics up while running the dyno.

with 36k lbs last week on parley's , i was at 20mph...

i'm headed west this afternoon from Topeka, with what looks like 40k.
I'm fearing the head winds and the hills. THere will be some PO'd Prime drivers having to drive the left lane to pass...oh the misery.
I'm hoping the dyno can also reveal my drive line issue( the vibration when coming off full power on CC) ride height has been checked , rechecked- and trip-checked. carrier bearing replaced.