The wait times at the border service centers are lower than the west coast USCIS service centers for green cards, so I don’t think you can say that is the issue

The wait times at the border service centers are lower than the west coast USCIS service centers for green cards, so I don’t think you can say that is the issue here. In addition, there’s a complex system with many centers over the US that deal with immigration and visas (and embassies in particular for the latter), which depend on what you are doing and where you are filing from. There doesn’t seem to be any correlation there.