Here are a few facts that I have recently discovered by doing some research.
The Watchtower Society uses the date of 539 B.C.E as the date that Cyrus took over Babylon. they use the term "absolute date" to define this as an unquestionable point in time. I find that only the Watchtower uses the term "absolute date". No one else, scholars, historians, etc. use this term. At least that's what my research reveals.
From the date of 539 B.C.E the Watchtower Society allows 2 years for the Jews to return to Jerusalem and start re-building the Temple. This brings us to 537 B.C.E. This is okay. Then they apply the 70 years of desolation mentioned in Jeremiah and arrive at the date of 607 B.C.E as the date that Jerusalem was destroyed by the Babylonians. From 607 B.C.E they count the 2,520 years (prophecy) and get to 1914. They count back from 539 B.C.E to a point in time, and then go forward from that point to get to 1914.
The problem here is that although history agrees with the 539 B.C.E date, history fixes the destruction of Jerusalem as 586 B.C.E, not 607. Every encyclopedia, textbook, scholar, historian and University I could find all agree on and use the date of 586 B.C.E as the date for the destruction of Jerusalem not 607. Only the Watchtower uses the 607 date.
From this I have concluded that the date of 607 is not the real date for the destruction of Jerusalem but one that only fits with the seventy years prophecy. Jerusalem never lay "desolated" for 70 years. It was only desolate from 537 to 586. That is 49 years. I seem to think that the watchtower used only the 539 date and ignored the 586 date because it didn't fit with what they wanted; the 70 years, the 2,520 years and 1914. 1914 was the goal, and they backed-into the dates to make them work. To do this they had to ignore 586 B.C.E which is the real date for the destruction of Jerusalem.
Therefore, if Jerusalem never lay desolate for 70 years, when does this desolation and fulfillment of this prophecy take place? When does the 2,520 years start? 1914 can't be correct. 1914 is based on 607, and 607 is only mathematical, not actual. 586 is the real date.