(a) The campaign treasurer of a general-purpose committee filing monthly reports shall file a report not later than the fifth day of the month following the period covered by the report. A report covering the month preceding an election in which the committee is involved must be received by the authority with whom the report is required to be filed not later than the fifth day of the month following the period covered by the report.
(b) A monthly report covers the period beginning the 26th day of each month and continuing through the 25th day of the following month, except that the period covered by the first report begins January 1 and continues through January 25.