Why is it that most books do not say 607 ?
Because that is not when Jerusalem fell, no reputable bible scholar believes that Jerusalem fell in 607. The Watchtower only clings to that date because it makes their chronology work. As justification they say that the bible makes mention of "70 years of desolation", which they insist is a literal time period that doesn't work with 587. But other groups reconcile the 70 years with the 587 date, and the Watchtower itself teaches that the 70 years of desolation is figurative in the case of the fall of Tyre. It makes no sense that "70 years of desolation" is figurative in one case but must be literal in another. It's clear that the Watchtower is insisting that the 70 years is a literal time period only because the 607 date supports their chronology of 1914.
Put that with their failed generation predictions and you can only conclude they haven't gotten one thing right.
For a complete explanation: