Except as otherwise specifically provided, for an annual statement that is required to be filed in the offices of the commissioner and that is delivered by the United States Postal Service to the offices of the commissioner after the date on which the annual statement is required to be filed, the date of filing is the date of:
(1) the postal service postmark stamped on the cover in which the document is mailed; or
(2) any other evidence of mailing authorized by the postal service reflected on the cover in which the document is mailed.