Honest question, are you sure? Here’s what it says on the Student Financial Services page. Sounds just like a first use, not first use at an institution.
"Individuals who first use Post-9/11 GI Bill program on or after January 1, 2018 will receive monthly housing allowance based on DoD’s reduced basic housing allowance (BAH) for monthly housing rates= $3,669.
Those that began using benefits prior to January 1, 2018 will continue to receive a higher monthly housing rate based in the non-adjusted BAH rates= $4,148."