OM602: Vacuum routing wrong...yet everything works perfectly

[shertex]

Noticed something today that confuses me. On my 91 300D, I've done a few things over the years with the vacuum system. I've done the wastegate conversion with the associated elimination of all the vacuum rat's nest on the passenger side. And, while my memory is a bit fuzzy, I may have done some other things to simplify the system.

Anyway, hadn't looked at it closely in years. But I noticed today that NOTHING is attached to the center of the vacuum control valve. But there is a tube connected to the "off center" orifice which goes to a damper and the splits to the vacuum pump and vacuum amplifier. But, the way it's supposed to be (see attached diagram) is that the tube that splits is attached to the center with no damper, and the the damper is attached to the off center part and goes to the vacuum amplifier switchover valve for the transmission.

My question: since it's obviously routed incorrectly, why does everything work perfectly?