I believe GS training helps most with those players who are on the far ends of ideal minutes for the week. So guys with 80+ min or very few.
So, it's possible that the GS training prevented drops that you would have had had you not done it. Did you have a lot of guys drop? Also, did you monitor their DMI? Cause that can tell you if the GS sublevels increased or not, regardless of popping or not.