We know people in the admissions department and every year the benchmark is moved up.

The formula for admission is always changed.  But it is a public fact that BYU tries to have a diverse yet balanced population.

More women then men apply to BYU (its something like 70% of applications are female). so for them to have a 50/50 population more women are rejected.  That raises the bar on requirements for girls to get in.

BYU also wants a diverse cultural student base. So they give more weight to students outside of Utah.  That raises the bar on the requirements for Utah kids.

Take a female from Utah and run her through the admissions formula and you have a severe handicap. 

It's harder and harder to get in every year...
https://www.sltrib.com/news/education/2017/12/03/leaked-documents-suggest-brigham-young-university-gave-enrollment-preference-to-men-but-thats-not-as-weird-as-it-sounds/