Debtor
Deut 18 makes no distinction between making an original prophesy or interpreting one already existing. Its just says if you claim to speak for God and your message doesn't come true - you're a false prophet.
Do the Watchtower claim to speak for God? Yes. They claims to speak exclusively for God, claims to be Spirit-directed by Him. They offer those "predictions" up as New Light from Jehovah many millions of times over, on a worldwide stage and then bring into question a brother's faithfulness and spirituality if he dares to voice doubts in the latest understanding with a possible outcome of being disfellowshipped and shunned.
Your clear desire to twist the Deut scripture tells everyone here that you are still captive to that basic concept that the WT Society is God's Organization, a concept that MUST be defended by you at all costs. You see - we know how and why you think as you do - we've all been there.