Probably the only benefit I would see in using consultants to look at ways to reduce consultants is maybe to get a second opinion in addition to the one that would be provided by senior public servants, who would advise ministers and cabinet on the best ways to reduce the use of consultants.
It would seem a bit risky to rely solely on the expertise of consultants in that perspective. I would see that as the only reasonable approach that would justify asking consultants for ways to reduce fees for consultants. It would be to confirm the advice that public servants would have already provided.