Just as with your ability to bend aerodynamics to suit your proclivities, you can sometimes embrace new versions of history that suit your need for "symmetry" in your life (and also that the forces of evil hold back the clearly superior designs that you love so much)!
The truth is not quite so boldly deceptive as you would wish (that web site you use as "proof" is a Luftwaffe web site that goes out of its way to show how wonderful everything was back then when Nazis ruled the known world):
The Flettner Fl 282 was very successful, and about 24 were built. It did operate from ships in tests in 1942, when only 3 experimental prototypes existed. That limited trial is what your web site photo shows. These sea trials were possibly before an R-4 landed aboard ship in 1942, I cannot find dates for either right now.
Regarding "rate production" I believe the story is also not so clear as your revisionist theorists would believe. Thanks in part to US 8th Air Force bombardiers, starting in 1942, a total of 24 282's were produced before production ended sometime around mid 1943. During that time, 130 R-4's were built and delivered to the US and British military from the Bridgeport plant. It could be that the R-4 was earlier, or that the two were contemporaries. By war end, over 400 R4's were delivered.
No doubt, the Flettner was very maneuverable, safe, and effective, and if its factory had not been bombed, it might have given the R4 a run for its money. As it is, the story is not as clear as you seem to believe.
http://www.centennialofflight.gov/es...ettner/HE6.htm