You need to be asking in the Kindle Developer's Corner
https://www.mobileread.com/forums/fo...play.php?f=150
I think there was a time when skipping a large range of updates was a bad idea, but I don't know.
It is known that it is safe to do the 5.9.6.1 jailbreak on a PW3 running 5.9.2 (did you read the thread?)