Yes, the payment stream is correct as you've stated. The lending staff is not required to attempt to guess what the rate would do, you just need to disclose that the loan IS variable rate and COULD change, and then it's up to the borrower to pay attention to what rates are doing.
(However, with all the uproar about ARMs, who knows what will be required of us in the future. If anyone finds a good deal on crystal balls, let me know.)
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I disbelieved what he was saying so hard, I probably created an alternate universe where it wasn't true.