(1) A paper document is filed with the Commissioner-General under a tax law if the document is

(a) delivered to an office of the Authority; or

(b) sent by post to an office of the Authority.

(2) A paper document is received by the Commissioner-General

(a) when the document is posted, as long as it is received in an office of the Authority within a reasonable time; or

(b) in any other case, when the Authority acknowledges receipt by stamping.