Maybe you should also mention that it uses 625lines 50Hz even in NTSC with a color carrier of 4.429..MHz, close to the PAL carrier. PAL was developed at the same time in West Germany and obviously already in that early stage not even considered to be used in East Germany. Only NTSC and SECAM was tested. The black and white norm in East Germany was in the late 50's (strangely) changed from what was used in the Soviet Union and the other east block countries to what was used in western Europe.  The main difference is the sound carrier, west 5.5MHz, east 6.5MHz from the picture carrier and of course different channel frequencies, even though some of the VHF band does overlap. So maybe some of the communist leaders did regret, that they made it easy to watch west German (B&W) TV and made sure, that we could not easily watch west German color. They decided with the rest of the east block for SECAM. There was a huge (black) market for add-on PAL decoders. I once demonstrated my first east German Color set from 1969 (all solid state) at one of the conventions using SECAM. However the norm converter was not good. I now was able to get a Snell & Wilcox broadcast quality converter and the SECAM signal is amazing. However SECAM is not as good as NTSC and PAL, even though it does solve the hue problem.

One more thing you may wonder about, why postal service. The postal service was in charge of all telecommunications in Germany, way back to the emporers days from 1871. Basically it was also the FCC. Telephone, radio, teletype everything.