I know of a school that changed from full to set rate. This was their reason, when at full they could only award a few awards. With the set they can award many more awards as they also use merit to bridge the difference.
Example: They used to give full, lets say 50 K. Now they give set (I can’t remember what the set amount for this year is but lets say 40K), so they give $10K in TE and $30K in merit to equal the $40K. This way they can give a whole lot more TE awards. Hope that made sense.
As @Intercoastal said I doubt they would change yours now. I hope you get the answer soon and please let us know what you find out.