A. A legislator or legislator-elect required to file an annual disclosure on or before February 1 pursuant to this article shall disclose his personal interests and other information as required on the form prescribed by the Council for the preceding calendar year complete through December 31. A legislator or legislator-elect required to file a disclosure as a condition to assuming office shall file such disclosure on or before the day such office is assumed and disclose his personal interests and other information as required on the form prescribed by the Council for the preceding 12-month period complete through the last day of the month immediately preceding the month in which the office is assumed; however, any legislator or legislator-elect who assumes office in January shall be required to only file an annual disclosure on or before February 1 for the preceding calendar year complete through December 31.