@Mastadon Tufts scored 75 on 2017 edition of the U.S. News with the top 10% metrics reported, and 72 for the 2018 edition without the top 10% metrics. Therefore, it seems clear that Tufts not reporting the top 10% metrics (3.25-points) precisely corresponds to the slip in the overall ranking & selectivity ranking. Given that the U.S. rounds up the raw score, if Tufts had 72.3+ raw score and had 3.25 points added up, it would have been ranked at #25 for the 2018 edition.
Also, it’s very unfortunate that a flawed source such as the U.S. News dominates today’s college admissions landscape.