They gave the MoH out like candy in the 1860s during which time units were sourced from a common location. That inject a A LOT of noise into the statistics.
Unfortunately I do not have the source to back it up, but I recall a Jocko or Jocko-adjacent podcast discussing changes in medals of valor at or just after WWII, shifting away from “charged a machine gun” acts of valor to “saved his team’s life” style events, not just for the MOH but for all prestigious medals.
Is that noise or data?
Noise, if it does not support the claim. Signal otherwise.