Fisherman:
Immaterial deflection.
Your skills at identifying what is and is not relevant and also of fallacies are remarkably deficient.
The subject matter here is 70 years in Babylon
Actually, the subject matter is the 'faithful and discreet slave', though the JW drivel about 607 is foundational to their interpretations about that subject.
which Zechariah confirms.
Wrong. Zechariah doesn't refer to 70 years of exile at all, nor to Babylon's 70 years. Zechariah (7:1-7) refers to annual fasts in the 5th and 7th months, which by the 9th month of Darius' 4th year (518 BCE) had been held for 70 years. This places the first year of those fasts in 587 BCE when Jerusalem was destroyed.
537+70= 607 —If you forgot the subject.
The Jews arrived in Jerusalem in 538 BCE rather than 537 so you're wrong there anyway, but that was only after Babylon was called to account in 539 BCE when the 70 years actually ended (Jeremiah 25:12). 539+70=609, which is the year that Babylon destroyed Assyria's final capital at Harran (compare Ezekiel 27:2, 23; Isaiah 23:13-15).
You can go now too.