wt scholars deal with Bible chronology based on the Bibical data primanily and are not dependent on outside secular evidence apart from determing a absolute or pivotal date.
Scholar, start at 539 BCE[pivotal date] a date WTS accepts. They also accept 17 years for Nabonidus rule, 4 years for Neriglissar, 2 years for Evil-Merodach and 43 years for Neb.Count backwards from Nabonidus, add 17 to 539=556, add 4 to 556=560, add 2 to 560=562 and add 43 to 562=605. History says Neb. begin to rule in 605. WTS says Neb. begin to rule in 624. If you subtract 43, 2, 4, and 17 from 624 you get 558 but if you subtract these years from 605 you get 539.History is right WTS is wrong. If you add or take away any from these four years you can't get 539 which is accepted for Babylon's fall.