Not having been to Okinawa myself I tend to listen to those with that experience.
Once during a discussion with George Donahue (a Kashiba Juku Shorin Ryu) stylist who was raised in Japan, was a youth Japanese TV star, and did train on Okinawa, he remarked about a point Shimabuku Zempo made to me in 1974. At that time he was the Martial Arts editor for Tuttle Publicans, then the best publishing house of Martial Literature IMO.
A host in Central Pennsylvania was having a clinic with Shimabuku Zempo in 1984, I had never seen that type of Shorin Ryu in my area and was interested. It proved to be subtly different from what I knew. At the party afterwards I had the chance to talk to him. He had lived in the US prior to that time, for a while, and knew Isshinryu karate-ka there. He was quite personal, telling me the best American practices on Okinawa were the beer and the chesese. LOL
Then he made a statement to me.”“That on Okinawa there were maybe a hundred Shorin dojo, maybe 30 Goju dojo and 3 Isshin dojo”. I believe he was making a gentle point about Isshinryu.
I was explaining this to George when George inserted then “and if you got to those hundred Shorin dojo, you will find each of them are doing a different version of Shorin karate:
I found that an interesting observation.