Institute of Medicine (IOM) recommendations on Vitamin D. What are they thinking!

On November 30, 2010 the Institute of Medicine (IOM) updated its Vitamin D recommendations to 600 IU/day for people below age 71 and 800 IU for those over 71. What are they thinking!

People living north of Boston, Rome and Beijing experience a vitamin D winter (when sunlight is too weak to produce vitamin D) for 4-6 months. As vitamin D is stored for approximately 2 months, without adequate supplements many people are deficient by December or January.

I was taking 2,000 IU daily and my blood test showed that I was below the acceptable range by January. Is the IOM challenging the accepted ranges used by laboratories across North America?