I would think in today's market and interest rate enviorment, the mortgage holder would not want to invoke the DOS clause. Most likely if they had to resell as REO, or reinvest their money in a new mortgage, they would receive a much lower interest rate. This is particuliary true if the current seller has not refinanced recently (because he may have bad credit, etc.)and has had the financing in place for a few years. Just my 2 cents