Is it normal for passenger front side to sag 1.5" when 2006 LS430

Got back from 3 wks in south Fla. Battery nearly run down, but managed
to start it so went shopping with chief shopper and I sat in car and
let it run to charge battery. Noted a qiet noise like a pump running
at times. This was yesterday. Today got in and drove out driveway and
car front bottomed on the end of the driveway where it joins to street
- had never done that before. Parked it and came back out and couple
of friends with me commented it looked low in the front. Drove off and
parked it again and when I came out I noted the right front fender was
down to the level of the tire and the left side wasn't. So I started
it up and drove off to a place I was sure was level, got out and
looked at it and it was level with the motor running. But I was
suspicious, so I drove to stealership and asked the nice young people
there about it. As we talked, the passenger front got lower and lower.
At time when the nice young service writter measured it with a tape
measure, there was about 1.5" difference in height. The wheel well was
closer to the tire on the passenger side, and the top of the tire was
nearly at the opening of the fender. The drivers side was higher, at a
normal height. Service writter called the shop and the expert in the
shop said it is normal for the car to sag when the motor is turned off
and the car compensates for the drivers weight by raising the drivers
side higher than the passenger. I have not noted this height
difference before. Is this actualy true that there is a normal sag to
the right of 1.5" when the engine is shut off? What is the "running
pump" sound I hear likely to be - I did hear it again today.

Anyone else notice this heigth difference or pumping sound?