My husband’s college roommate tested out of several classes but decided he should take the classes to get a cushion in his GPA as he was an electrical engineering major and knew it would be competitive. He GPA ended up being a 3.5 due to the fact that he retook classes he had taken as AP classes in high school. If you place out of something like history which will not be in your major then I would do it. But, if it is calculus and the next level is difficult then I would do what the other posters have said and examine the final from the previous year.