J/30 Class Association Forums J/30 Forum Racing Tools and Techniques PHRF rating ??????

Could you all give me a little feedback on your PHRF RATINGS? I have raced J-30's for the past 20 years. Our rating has always been 141 spin class and 147 cruising. PHRF NE wants to change my rating for 2009 to 138 spin and 147 cruising. I do not understand. I have the same equipment. all standard. anyone have a clue why after 20 years they think the boat got faster??????