The data saved for the game is stored on the PSN and Ubisoft servers.
And if you want to RE-SIGN / RE-REGION the save, it won't work!
It took me a while to discover this problem!
And I took a 100% save from a friend and re-signed it, switched it to my PS4 system, got into the game and it came to nothing!
Then I realized that the save was not stored on the system, but on an account in the Ubisoft cloud.