Sorry but you have your figures wrong.
You are receiving a 10+ yield on the purchase price, not the current market value. On current market value im sure your yields will be under 10%.
If you are offering people 10% on there investment which at 50% x 2 = 100% of the investment cost you will have negative cash flow.
You cannot compare your yield on purchase price to the yield on their investment and call them the same.
Ta
I calculate the returns on the purchase price, or the mortgage. Not current market value.