I think the GB is trying to reduce fixed cost. Circuit Overseers, Bethelites, Missionaries, etc.
Most of these people are getting older and cost more. When you cull the FL congragations, you automatically reduce the amount of Circuits/KHs which also translate to reducing the number of COs. That will be a big chunk of change to save.
In some part of Central Europe, we just heard that a few congregations where merged and they have about 180 publishers in one congregation and about 160 publishers in another congregation. This means $$$$ for the JW as they can sell execess KHs and get rid of excess COs.