Make a simple table with one row per quote: cash due at closing, monthly payment, interest during the year, mandatory fees, balance after one year, early-repayment consequences, and portability conditions. Then add two renewal assumptions rather than one. That should expose whether you are...
There is a caveat with treating every withdrawal as shadow supply: some homes may no longer be available at all. I would track them separately rather than adding them to active inventory. For the practical buyer question, recent completed sales and the number of genuinely comparable new listings...