BAH Correction on Orders

I’m AGR and PCS’d to a reserve unit in Maryland, but my orders incorrectly showed Fort Meade (location of the higher headquarters). I contacted my higher echelon to fix my orders, but when I did they informed me my BAH would go down. Problem is, the travel.osd.mil (BAH calculator) website shows it should be going up by about $400. Is there a reason why they say it’ll go down and everything I’m seeing online says something different? Is there a way to contest the BAH amount of it does go down?