and on the other hand using WorkoutCreator to make a copy may give good results like simply making a copy. However PLs of sprint workouts in TR can be a little wacky because % FTP of the custom workout is taken into consideration:
even though the workout text states:
so if you create a custom workout and bump % FTP of a sprint to accurately reflect your % FTP, and its greater or less than (an equivalent) TR workout, you end up with a custom workout PL that is skewed relative to TR workouts. Even though the TR workout tells you to do a max effort.