If the program manager of a major defense acquisition program for which a unit cost report has previously been submitted under section 4372 of this title determines at any time during a quarter that there is reasonable cause to believe that the program acquisition unit cost for the program (or for a designated major subprogram under the program) or the procurement unit cost for the program (or for such a subprogram), as applicable, has increased by a percentage equal to or greater than the significant cost growth threshold; and if a unit cost report indicating an increase of such percentage or more has not previously been submitted to the service acquisition executive designated by the Secretary concerned, then the program manager shall immediately submit to such service acquisition executive a unit cost report containing the information, determined as of the date of the report, required under section 4372 of this title.