hey dr kevin,
i am in the same situation you are in. however, being the paranoid person that i am, i practically e-mailed every single school inquiring about multiple mcat scores. majority of the schools said that they take the most recent score, and many also said that they take the best score. also, they all said that they take improvement into great consideration and that if you hold your scores, they assume the absolute worst. so, release all of them. if you've improved, it will only help you!