I don't think you analyzed the market much when rate shopping. I've been following ratespy.com for the past a few years and you *definitely* get lower rates with insured mortgages. It's not that they charge you more with 20% cashdown, it's the other way around, you get "rate rebates" when getting insured mortgages. I've seen this from many lenders, mostly non-big bank lenders though, like MCAP.