My SL has SLS on all 4 and it doesn't drop. My 16v has SLS on the back and it does not drop. Are they similar systems to the 560?

I saw this post earlier and I am curious about the cause and solution, in case it ever happens on my SL.

My thoughts are that maybe the levelling control valve is leaking by, allowing oil to flow back to the reservoir.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport