Not long after the video came out with Splane and his chart explaining this generation thing I phoned an elder and used this very scripture in Matthew and said, "There. That's how long a generation is according to the Bible. You don't need charts to tell us how long a generation is." And believe it or not he actually agreed with me. But he didn't really say much after that and kinda just mumbled that we need to go along with the slave.
So I didn't really argue with him much and kept status-quo with him to keep the relationship, neither agreeing nor disagreeing, but simply stating that to me, I wanted to stick with the Biblical definition of a generation. And that was about the extent of the conversation. I wish I had a big "ta-da moment" but sorry, just reality.