No, it's not normal. The EZL does not allow vacuum advance at idle and idle timing is fixed by the EZL and cannot be adjusted. In fact I block mine for emission testing and the idle remains at 700 in neutral (five-speed manual trans). Idle is sensed by a switch on M103s and there is a connector on the top of the inlet manifold forward of the fuel distributor that allows you to easily test it.

The rate of spark advance with engine revs is established by the R16/1 resistor. Removing the resistor creates the most aggressive ignition advance curve with RPM, which will yield best performance and fuel economy, and replacing the resistor with a shorting plug is the least aggressive, which will improve emission test performance.

The location of the R16/1 varies by model... inside side of the battery compartment on 201s, and I think it's located near the master cylinder on 124s... not sure about 126s.

Search for threads started by me about ten years ago for more information on the above and the effects of various changes, especially on EGT and emission test performance.

Duke