If an inside lawyer cannot call a partner to instruct the firm without first getting permission from a superior, that is a gating process. Without having to obtain approval, the first lawyer might not have thought much about the cost; with an approval process, even a minor delay and explanation will serve to moderate costs, improve the choice of firm, and assure timeliness.
A further advantage of gating is that the disclosure process can require the instructing counsel to estimate the amount of payments to be made to outside counsel. This step may create more of an administrative burden to track but it does put the inside lawyer to some degree on the line for cost control.