Chevolet P30 Shocks

Depending on your front suspension 70 pounds may not be enough.
I had a 96 motor home on a 95 P30 chassis. The vehicle owners manual described how to set the pressure in the airbags. In case you don't have the manual this is what mine said:

The owner’s manual gives the following ranges:

4,300 LB front suspensions = 10 psi to 50 psi
5,000 LB front suspensions = 40 psi to 50 psi
5,300 LB front suspensions = 50 psi to 80 psi
5,500 LB front suspensions = 60 psi to 100 psi

For the proper adjustment it says to inflate the air bags to the maximum pressure for your vehicle, load the motor home, park on a level surface and then reduce the air pressure as needed to level the motor home but don’t reduce it below the minimum.

X2 yes, check the springs. Also, is there anything causing offending weight (out of the norm) on the coach?

No. Springs may be shot. When I needed new bags on mine I ordered new springs from Henderson super steer and ditched the bags. The springs are matched up to your front end weight.

Some good reading for the P30 Here

Also when you inflated the bags I believe the proper way is to lift the front end up then inflate and lower onto ground. I would put 90lbs in mine lower and bleed off.