M137 V12 expert advice wanted

[JeffreyNMemphis]

Hello Peaches,

I am seeking expert on the M137 V12 to offer advise on installing a tiny LED that will indicate if Cylinder Shut Off is functioning. I am getting about 15 MPG in city/hwy and 17 mostly highway. I have read that CSO can increase mileage to 22 MPG. Have been driving the car daily for a month and never seen 20 MPG.

The model is 2001 S600 sedan.

Do you know the circumstances that turn on CSO? Is it a gear and RPM function?

It may be that previous owner's technician turned off CSO. How can I know?

Thank you in advance!