Hi Doug
I am somewhat taken back by your surprise that WT scholars rely on secular data in order to construct a scheme of Chronology because have I not said repeatedly on this forum and others that the WT Cfronology in relation to the calculation of 607 BCE and other OT dates that secular sources whether astronomical or otherwise are necessary in order to count back in time. Really, what your response shows that you have an inadequate understanding of the role of METHODOLOGY in Chronology and this was the fundamental purpose or thesis of Rodger Young's article.
Simply put, Methodology allows WT scholars and any other Chronologist to cherry-pick if you like what secular data is required especially when the historical data or biblical data such as the 70 years conflicts or is not in harmony with a traditional methodology with the reliance on different calendations and astronomical data.
Previously SDA scholars championed VAT 4956 pinpointing Neb's 37 th year using astronomical data which would disprove WT Chronology and 607 BCE. But the tables have turned on such scholars because of the research of Rolf Furuli whose thesis shows that Neb's 37th year can be assigned much earlier confirming Neb's 18th year in 607 BCE which is proved by Jeremiah's seventy years.
scholar JW emeritus