The head of each budget unit, not later than October fifteenth of each year, shall submit, on forms prescribed by the Bureau of Finance and Management and in the manner deemed appropriate, such explanatory data as required and necessary to adequately convey the budget requests, to the Bureau of Finance and Management estimates of the financial requirements of his budget unit for the next fiscal year. The estimates so submitted shall first receive the approval of the board or commission of each budget unit for which a board or commission is constituted. Not later than the November first following such submission, copies of such explanatory data of the budget requests shall be transmitted to the Legislative Research Council by the Bureau of Finance and Management.On or before September first of each year, the head of each budget unit shall submit, to the Bureau of Finance and Management, on forms prescribed by the bureau, the explanatory data needed to adequately convey the financial budget requests of the budget unit during the next fiscal year and changes to the current fiscal year. If the budget unit includes a board or commission, the board or commission must approve the budget requests before submission in accordance with this section. On or before October first, the bureau shall transmit the budget request data, together with explanatory information, to the Legislative Research Council. 20