185.57 is the correct payment IF the rate is quoted as 8.7% annual

compounded monthly.

184.41 is the correct payment IF the rate is quoted as 8.7% EFFECTIVE

annual compounded monthly.

Rate needs to be converted:

(1 + r)^12 = 1.087 : after compounding, result is 8.7%

r = .006976.... (monthly)

.006976 * 12 = .0837122.... (approx. 8.37%)

In other words, an annual rate of 8.37 if compounded monthly

will result in an EFFECTIVE rate of 8.7%

Hope that helps.