Question about limp mode and rear air suspension - W211



I am searching for used W211 E63 and looked at a 2008 this past weekend. There were a couple quirky things and wanted ask about them. This was at a dealer, had 80k on it. When I got there the car had been sitting for about 10 days according to the sales guy. The rear air bags were clearly deflated as the car was sitting very low in the rears. They said its normal since it had been sitting. Well there was no issue up front. Anyway, once the car started it raised and sat at normal height. My suspicion is that its is a minor leak or issue but not sure. Is this normal?
The other issue is that the car would not rev past 3k rpm when sitting there running. I would floor the car and it would just max at 3k. Some quick googling on my phone revealed the 'limp home mode' which I had never heard of. Anyway I went for a test drive and the car was going past 3k fine while driving but even after a 10 min drive, once I put the car in park it would not rev past 3k. Again, normal according to the sales guy. Maybe the computer was off since the car had been sitting?
thank you
not reving past 3k at 0mph is normal.











