If a State or local government voluntarily contributes its own funds to supplement activities carried out under the applicable programs, the State or local government has the option to separate out the Federal funds or commingle them. If the funds are commingled, then the provisions of this subpart apply to all of the commingled funds in the same manner, and to the same extent, as the provisions apply to the Federal assistance. State funds that are contributed pursuant to the requirements of a matching or grant agreement are considered to be commingled funds.