I think the discrepancy comes from whether the vehicle has navigation or not.

This is how it works on my 2008 W164, YMMV...

My vehicle has navigation, so it automatically sets itself. The time zone offset is all you can change. It defaults to US Central - perhaps an homage to its birthplace?

I have yet to drive it across a time zone boundary yet. Our Pilot had navigation and once when we drove to Alabama, it automatically rolled back an hour at the exact instant we crossed the GA-AL line.

If you don't have navigation then you have to go into the console menu with the steering wheel buttons to set it.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech