Just be patient. You won't have a real number there until a month goes by and you've received a first payment on all of your notes. The math just doesn't work now with only $0.34 interest received and all of the principal you've invested. If all of your notes make their first payment, you will see a much higher rate close to 16.91%, but don't get too excited about that either.....over time it will drop some as you have defaults....and you will have some.

I'm nearly 3 years into investing and add new funds each year and reinvest all payments. My weighted average rate is 18.96 and my NAR is shown as 13.26 right now. If I turn on the adjustment for late notes it shows as 11.16 which is pretty much what I get if I calculate my return in Excel with the XIRR function.