Like Tuscani said, 10% down isn't needed... 5% down will qualify you for more programs than $15k down, but there are still 0% down financing programs available these days. If you have less than 5% down, and your financed loan amount will be over the conforming limit (which is $417k on a 1-unit in CA), I'd just recommend you keep the $15k and apply for 100% financing, as rates don't get any better until you put 5% down. Your DTI and credit scores should be just fine. On a $500k sales price, you are probably looking at more of a $3,700/mo payment with property taxes & homeowners insurance... and if you have PMI it'd be closer to $4k-4.1k.
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