Benefit of Cross-Charging Functionality

I am working on a Projects implementation for a client with employees owned by 2 legal entities who charge hours to projects owned by many other entities. They are also using Total Burdened Costing. There are many legal entities in a single ledger. In their current version (12.1.3) there are many balancing segments in a single ledger, but few defined legal entities. In 12.2.8 the legal entities are all defined, and each is associated with a balancing segment. The project owning organization should get a debit for the labor cost, and the resource's organization should get a credit, posted to