I have a 380SE, 1985, and the same set-up was in my old '75 450se. If you notice, the resevoir is designed to fill the radiator from the bottom, to push the air to the top. The hose leading from the top radiator tank to the resevoir is designed to allow entrapped air to bleed to the top of the resevoir tank, out of the coolant as it circulates, but still within the sealed and pressurized circulation system.
The overflow tube from the cap is on the other side of the cap seal, and doesn't allow any loss of pressure (or air) until the cap spring is overcome. This design is quite different from most sealed systems, I think.
The highest point in the system is already inside the top part of the resevoir tank, where all the air entrapped in the coolant will eventually go. I see no need to manually elevate the car to 'burp' the air out.

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1986 560SL
2002 Toyota Camry
1993 Lexus