Obviously neither is a stated, integral part of the HC at BYI. Bit idto they everin became such, I wouldn't lose sleep over it. One is essentially a commandment by way of repeated prophetic counsel (FHE); the other is fulfilling in part a covenant which most male members of the church have made (duties inherent as part of the Oath & Covenant of the priesthood).
This is not an attempt to be preachy or self-righteous. None of us are perfect...that's why we're here. And BYU standards help to that end; though living by BYU standards isn't all-inclusive of celestial standards.