On recent experience
LHR-ADD showed the Safran seat map up until the inbound flight departed Addis, when it updated to the Diamond Parallel
ADD-CPY showed wedgie seats up until boarding started (pretty much) when it became Diamond Parallel
Disappointed not to try the Safran seat, but happy as I find the Diamond Parallel very comfy indeed. 6 hours solid sleep from LHR and a nice nap onwards. Throughly enjoyed the ET service too, comfortably the best long haul operator in Africa IMHO and joint top with Airlink as best African airline. ADD is a little bit of a zoo for transit (was surprised to find a central transit security which was not well organised). But it worked
My return home on an MS A330 was quite the comedown...