I'm going to stop being lazy and work out the decision tables properly for myself like I've done previously
Wow! Kudos! It would take me so long to unscramble all the data and set it out logically - as interesting as the project might be. That's why I like the one Young has already prepared :-)
I've categorically determined that Ezekiel, Jeremiah and 2 Kings (for the period in question) use Tishri dating and count accession years. Daniel uses Nisan dating and does not count accession years. And it's resolved a minor problem I'd had with the reign of Jehoiakim
Yes, Daniel and the end of Jer. 52 seem to be using the standard Babylonian accession method of counting.
Young concludes that,
- (certainly from Josiah onward) the T-T method was used for Judean kings in Jeremiah, Ezekiel and 2 Kings;
- for Babylonian kings in 2 Kings, N-N and non-accession is used;
- for both Babylonian and Judean kings in Jeremiah (but not the end of ch. 52), reigns were counted in the non-accession way. It's uncertain whether Babylonian kings were counted T-T or N-N here as both scenarios work;
- Josiah's reign in 2 Kings was counted T-T, accession!
- weirdly, there was a switch to non-accession reckoning in the case of Zedekiah in 2 Kings/Chronicles and Jeremiah.
See also the other article by Young, pp. 228, 246.