The Project Contract Funding Limit controls transactin at the most granular level of the WBS. Each node on the WBS has a funding limit that is compared when transactions are entered. The funding limit does not require a project category which allows entry up to the limit on the node regardless of category.
However several clients would like to control the funding limit (a form of budget control) at a rollup level of the WBS. Transactions charged to each WBS would roll up to a higher level to check the funding limit.