I bought a 2009 R350 with P1 package. The car suspension sags down noticeably after it is parked on the level place for about a week.
At 1st time, I noticed that rear passenger side sagged down by 1/2~1 inch, which is gap between tire and body. After I drove a short distance, it backed up to the same gap size to the other three. The 2nd time, both rear sides sagged down by same amount and backed up again after a short drive. I asked mechanics at the dealer, and was told that was normal.

Is this sagging normal? Any cause for this?

Thanks,
-Frank