A 20 year 30 million loan at 17% interest rate has a monthly repayment of Kshs. 440,040/=.
Adjusting the same loan to 27% without changing the repayment period increases the monthly repayments to Kshs. 678,252/=. A 54% increment in monthly repayment amount (Though a casual eye might 'see' a 10% increment). Adjusting the payment period makes things worse in terms of interest payments but at least spreads out the pain over a long long time!!!
That is how fast you can get screwed!!!
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.