The contracting officer may insert the clause at 5352.216-9001, Payment of Fee, substantially as written, in Section B when the clause at FAR 52.216-8, Fixed Fee, or FAR 52.216-10, Incentive Fee, is used. The contracting officer may modify the clause, provided that the modification does not permit payment of the fixed fee or target on the basis of actual expenditure as a percentage of total estimated cost.