Built the house in 2004. R42 kraft paper faced batts in ceiling. Kraft paper toward room side of ceiling. No plastic vapor barrier on ceiling or walls. Two 3' ceiling fans run at low speed 24/7 during the heating season. Soffits are fully open and air has an unobstructed flow up and through the full length ridge vent. Heavy frost on entire roof each sub-freezing morning. No bare spots in the frost. Frost does not evaporate untill sun melts it away. Enitire attic area appears to have excellent ventilation. Interior ceiling is painted wallboard. First coat is Benjamin Moore primer (NOT PRIMER /SEALER). This is covered with two coats of Benjamin Moore off-white latex. I watched all the work being completed and the various contractors seemed to take great pride in their work. This year I have noticed some light gray "shadows" on the ceiling -NOT on the walls. These "shadows" appear to be defining the scissor trusses (16" O.C.) and perhaps some gaps in the insulation. I am unable to climb ladders to the easily accessible attic area which contains a switched 100 watt light. My first impulse to remove the "shadows" was to apply a good primer/SEALER over the existing paint and two coats of the existing Benjamin More color on top of the new primer/sealer. This would "hide" the problem. However, if there is a problem with the insulation or vapor barrier I want to fix the problem before re-painting. I want to get some feedback from our Hearth members who have experience in this area before I call a contractor. Best wishes, good luck and Happy Thanksgiving to all.