Selecta or Superba: Which is the Mercedes K45 Portable Typewriter Descended From?

Little did I think at 2.27 this morning, still half asleep as I waited to (unsuccessfully) bid on a nice burgundy woodgrain Rheinmetall portable typewriter on German eBay, that I had opened a small can of worms. As I waited, I posted on my Mercedes K45, saying that it was directly descended from the Mercedes Selecta, not the Superba, which I already knew (from my own collection) to have a distinctive high, bulbous top plate. The Selecta (which I also own) and K45 have flat, sliding ribbon spool covers, as well as the same switch on the left of the front panel. What's more, I am unable to find any images or written material confirming the existence of a Mercedes K50 typewriter. The only Mercedes K50 I can find is a car. Was a K50 typewriter ever made?
This is what I believed had confirmed my impression of the Selecta-K45 lineage:

 Ernst Martin's Die Schreibmaschinen und ihre-Entwicklungsgeschichte (1949)

Leonard Dingwerth's Die Geschichte der Deutschen Schreibmaschinen-Fabriken, Band 1 (2008):

These are images of my Selecta, K45 and Superba

Note the spelling on my model is "Selekta" and on Georg's it is "Selecta". "Selecta" is the more usual.

Here are some other Selectas and K45s:

Georg Sommeregger Collection

Here are some more Superbas:

Richard Polt Collection

I'll let you be the judge as to which the K45 is descended from. In my opinion, the answer is pretty obvious and lies quite evidently in the design of the machine.  Do you believe your own eyes, or lists of numbers which include a non-existent typewriter?