Goldminer,
For your wifes sake maybe an even simpler approach would work. I have found that as soon as you get into chronology most people just tune out and assume the Society knows what it is talking about.
For what it's worth. you could approach the whole 607 thing like this:
Goldminer to Elder: What does Nebuchadnezzars dream in Daniel Ch 4 have to do with 1914?
Elder: The dream means blah blah blah, and when you add this scripture, plus this scripture, that's how we come up with 1914.
Goldminer: It sounds like a secret code to me. Why do you suppose that Jesus or his Apostles never taught about this, did they overlook something?
Elder: (who knows what he will come up with)
Goldminer: Well if you keep reading on in the book of Daniel, only a couple of paragraphs later, Daniel himself explains exactly what the dream means, how long the time period lasts, and what the significance of it was. (Read on in Daniel 4) Was Daniel wrong?
Elder: No, .... it has a dual fulfillment.
Goldminer: Say what? Dual fulfillment.....what does that mean? What in the Bible leads you to believe this has a hidden meaning - could you show me? (insist on him showing you)
Elder: (Who knows what)
Goldminer: That's not talking about a dual fulfillment. Daniel says exactly what Nebuchadnezzar's dream means. Jesus and the Apostles never alluded to a dual fulfullemnt either. Maybe that's why all of the Society's predictions about the end of the world have turned out wrong.
Elder: (Lot's of BS)
Goldminer: I don't read anything in the Bible that leads me to believe in a hidden meaning. But Daniel 4:24 says right here “This is the interpretation, O king" The interpretation is right there in the Bible. Why are you going beyond what is written?
Goldminer: Haven't these kind of "dual fulfillment interpretations" gotten the Society in trouble before, by predicting the end of the world?
Elder: No
Goldminer: How come the first time the Society tried to use this formula they came up with different dates for Armageddon? And wasn't the 1925 end of the world prediction based on the dual fulfilment of the Jubilee cycle?
Elder: I'll have to do more researchGoldminer: Everything you need to know about Nebuchadnezzars dream is explained by Daniel himself. If it had an alternate hidden meaning surely Jesus or his Inspired Apostles would have at least touched on it, but they didn't. This type of speculation is precisely what caused the Society to make all of those false predictions.