Watchtower has not discussed every verse in the Bible, but that really doesn’t matter in the end. They’ve a creed that must be adhered to, even though they would deny they have a creed. Of course, Watchtower denies interpreting the Bible at all. That is what “Christendom” does.
But what happens if you don’t believe an interpretation? That could well be apostasy. And if you speak it aloud? That could easily land a person in a judicial committee. Thus a person would not be “waylaid” by one elder, but pulled into the backroom with three elders. The results could be your family, friends, acquaintances, you entire community and social network shunning you, not saying so much as hello if they see you on the street.
“Approved association with Jehovah’s Witnesses requires accepting the entire range of the true teachings of the Bible, including those Scriptural beliefs that are unique to Jehovah’s Witnesses.”
Even if it is not theological in nature, say a person pointed out cases where the Governing Body change their teachings from their own publications, or show where they became a NGO of the UN. That would be called “causing divisions”. Same result.
I suppose if you said that the “new light” was what you’d already figured beforehand, you would be okay. As long as it doesn’t contradict “present truth”. However, if you mentioned the “new light” BEFORE the Governing Body revealed it, then you would be accused of “running ahead”. And if a person got disfellowshipped, then the Governing Body changed the teaching then, you would not get an apology, and likely a person would still have to work going through the hoops of reinstatement.
Can they have it both ways?
Yes, about this and many things. They are a cult. They have absolute authority. They can have their cake and eat it too.