(a) The contracting officer shall not execute a contract modification that causes or will cause an increase in funds without having first obtained a certification of fund availability, except for modifications to contracts that -

(b) The certification required by paragraph (a) above shall be based on the negotiated price, except that modifications executed before agreement on price may be based on the best available estimate of cost.

(c) In accordance with 10 U.S.C. 983, do not provide funds by contract or contract modification, or make contract payments, to an institution of higher education that has a policy or practice of hindering Senior Reserve Officer Training Corps units or military recruiting on campus as described at 9.110. The prohibition in this paragraph (c) does not apply to acquisitions at or below the simplified acquisition threshold or to acquisitions of commercial products, including commercially available off-the-shelf items, and commercial services.