Income vs CMA approach...am I overpaying?

[Eric Zdanowski]

So I'm currently analyzing an off-market lead and need help pinning down a fair market value to determine what I can offer. 

Backround: This property is a SFH, but due to it being in a college town and consistently rented by students, it commands much higher than market rents ($2500/mo). Now, the seller is a sophisticated investor and works as a commercial loan officer, so he based his asking price ($225,000) off of the income approach using an 8 Cap. When I ran a CMA, however, comps put this property in the $180k-190K range. The thing is, even when I run the numbers at his AP, the deal more than meets my minimum ROI and Cash Flow criteria. My concern is that since this technically is a residential home, it would appear as though I am overpaying based on comparable sales. My worry is that this takes away my margin of safety and can affect my ability to finance/refinance.

So my question is: Is it unwise to pay more than comps would suggest, even if the rental income can justify the higher price?