California Code, Public Resources Code - PRC § 3407.5

If the person filing the report required under Section 3406, by error or otherwise fails to include the full amount of oil or gas production in the report, the department shall make an estimate of the deficit, based on the monthly production reports filed by such person under Section 3227, and add it to the report.  The department shall make a reasonable effort to reconcile the yearly report filed under Section 3406 with the data filed on the regular monthly production reports, before proceeding to change the report, but failure to do so shall not invalidate the assessment.