The JW chronology is indeed very badly flawed.
A few more quick examples of problems introduced by their baseless interpretation of 'kingship' at Daniel 1:1:
- In their interpretation of 2 Kings 24:1-6, the JW chronology bundles up Jehoiakim refusing to pay tribute, the subsequent marauder bands and Jehoiakim's death all up into just a few months from late 618BCE until early 617BCE. However, a comparison with lines 9 to 11 on the reverse side of BM21946 confirms that when Jehoikaim stopped paying tribute after 601 BCE, "marauder bands" were sent against Jerusalem in Nebuchadnezzar's 6th year (for about 3 months, starting from December 599BCE), and Jehoiakim died when Jerusalem was sieged a year after that (December 598BCE).
- JWs (The Watchtower 15 October 1964 p 636; Insight I, p 1269) say the Bible "does not disclose" why the "copper fetters" were not used on Jehoiakim in what they call 617BCE. However, a comparison of 2 Chronicles 36:6 with Kings 24:1 (and lines 12 and 13 on the front of BM21496) indicates that it was in Nebuchadnezzar's accession year (February 604BCE) that the copper fetters were to be used, but Jehoiakim avoided that by paying tribute.
- Insight (I, p 791) guesses that the '30th year' at Ezekiel 1:1 'might' be Ezekiel's age at the time. However, when the Bible's chronology is used, it becomes apparent that it was actually the 30th year since the "Book of the Law" had been found in the temple (2 Kings 22:3, 8).