A public service company shall file its annual report with the Commission within the time the Commission sets after the end of the year that the report covers. The Commission shall provide each public service company with a blank form of an annual report in time to allow the public service company to comply with subsection (a) of this section. Unless the Commission notifies a public service company of a proposed change at least 6 months before the start of the year for which an annual report is due, the Commission may not change the form of the annual report in a way that requires the public service company to change the manner or form of its record keeping.