Fast-pitch softballs

Question
I coach a (American) girls fast-pitch H.S. team here in Germany.

Recently, we had the Europeans and for the first time, they combined the DIVISION I (larger amount of student) and DIVISION II (mid-size student).

In the tournament, we used Wilson .47 cor softball with the NFHS marking which meet the requirement. However, all season long, we been using the Rawling .47 cor softball with the NFHS marking. The point I am trying to make is that, our pitcher who has the fastest fast-ball could not throw her hardest fast-ball, it would zipped about 5 - 8 feet above the catcher. She told me that the softball felt like very light. I contested it to the umpire before our first round robin game and they look at it. I gave them a Rawling softball that we used all season to compared to the Wilson softball that is being used in the European tournament. They, us and even you can obvious tell the different when holding both softball. But according to the umpire, they said that the tournament had issued the balls and that the ball did meet the NFHS requirement.
I thought that this was not fair, because every team knows our pitcher is awesome. She had to take some speed off of her fastball, it still was fast enough, but when we played good team, they were hitting her. Normally nobody could hit her. For example, this one DIV I team who is the DIV I champion and us being the DIV II champion, we played them in a doubleheader in the season, they were supposing the best team and our pitcher beat them easily with her fastball, changespeed and changeup. But due to our pitcher had to take some speed off her fastball, other team could hit her.
What your comment on this?
Thank you for all you doing...

Answer
Hi Richard,
A ball must meet certain requirements such as cor, minimum weight, circumference, ect.  If it does that it can be certified.

I know different balls feel different but an umpire has no authority not to use the tournament balls supplied.

Sorry I can't be more help.
Mark