All I can tell you is this, I practiced more versions of the same kata than I care to remember. According to my research, the problem occurs in the personal nature of the kata. I have read that sometimes a Chineese practioner would make slight modification when they would show an Okinawan a Kata. Not knowing it's origin, the Okinawan taught the kata that way. He may have made modifications as well. By the time the students learned this and moved on to their modifications you can see how things changed a bit, kinda like tracing your hand. If you look at the Motobu, Mabuni Kyan era, many of that era made subtle changes so that people would recognize it as their particular interpretation of their art. Shito ryu for example had many Ryu-HA within Shito Ryu, Kuniba-HA, Hayashi HA, Motobu-HA and each has it's own flavor. My guess this happened as well from China to Okinawa. Look at the White crane Kata, Hakutsuru and you will find umpteen versions.... Trying to find this out will be tough. the one thing I do know is that Bunkai DID NOT come out of Tegumi. I have been fortunate to see an old book written in Japanesse from the 20's and Tegumi looked like Sumo. It is my understanding that Choki Motobu was the first to really apply Bunkai to fighting, and he did this with the Nihanshi kata. I am sure other styles will have a background in Bunkai as well, but from my research, Motobu was the first to publicly say that this technique came from kata.