Standard&Poor's Ratings Services assigned its 'AA+/A-1+' rating to Michigan State Housing Development Authority's single-family housing revenue variable-rate bonds series 2007 D-2007 G based on: Very strong quality of the mortgage loan collateral consisting of predominantly FHA insured and VA guaranteed loans; Historical performance of mortgage loans consistent or below Mortgage Banker Association (MBA) statistics; Sufficient reserves for Standard&Poor's forecasted loan losses at the 'AA' level; Very Strong cash flow strength with current asset liability parity of 118%; Strong credit quality of investments; and Support of Housing Finance Authority (GO rating of 'AA'). These strengths are offset by the following weakness: Declining cash flow asset to liability parity ratio. The authority is issuing series 2007 D, E,