I have installed the Firestone Air Bag system on my Dodge 2500. Should I fill them up so that the trailer is level when towing? I have done that which required about 25-30 PSI on each side (before hitching up the trailer). When driving on the highways, the ride is quite smooth. When hitting dips in the road or driving in town and hitting the usual street conditions, the trailer seems to take more of a hit than it did before the air bags. Some things seem to move around in the trailer more than they used to. Is this normal and to be expected?