If you hitch and adjust your WD bars before adding air, then, when you add air, you raise the rear of the truck (reducing tension on the WD bars) and unload weight from the front axle and trailer axles. Essentially, what you're doing is the same as most of us do when hitching. The only difference is that we use the trailer tongue jack to raise the hitch to decrease tension on the bars (so we can install them in the brackets easier) and you're using the air lift system to raise the truck, which also reduces tension on the bars.
From all the instructions and theories I've read, the procedure is to
1. Hitch the trailer
2. Set the air lift pressure
3. Adjust/set the WD bar tension to bring the TV front axle back to the "unhitched" measurement.
It's my understanding that if, after adjusting the WD bars, you change the pressure in the bags, then you "should" readjust the front measurement by readjusting the WD bar tension.
ADDED: Here's what Air Lift says:
https://www.airliftcompany.com/works...s-air-springs/
The last sentence: "Adding air may require readjustment of the bars."