(a) No computations of annual gross dollar volume are necessary to determine coverage or exemption in those enterprises in which the gross receipts regularly derived each year from the business are known by the employers to be substantially in excess or substantially under the minimum dollar volume specified in the applicable provision of the Act. Also, where the enterprise or establishment, during the portion of its current income tax year up to the end of the current payroll period, has already had a gross volume of sales or business in excess of the dollar amount specified in the statute, it is plain that its annual dollar volume currently is in excess of the statutory amount, and that the Act applies accordingly. The computation described in paragraph (b) of this section, therefore need not be made. Nor is it required where the enterprise or establishment has not yet in such current year exceeded the statutory amount in its gross volume of sales or business, if it has had, in the most recently ended year used by it for income tax purposes, a gross volume of sales made and business done in excess of the amount specified in the Act. In such event, the enterprise or establishment will be deemed to have an annual gross volume in excess of the statutory amount unless the employer establishes, through use of the method set forth in paragraph (b) of this section, an annual gross volume of sales made or business done which is less than the amount specified in the Act. The method described in paragraph (b) of this section shall be used, as intended by the Congress (see S. Rept. 145, 87th Cong. first session, p. 38), for computation of annual dollar volume in all cases when such a computation becomes necessary in order to determine the applicability of provisions of the Act.

(b) In order to determine, when there may be doubt, whether an enterprise or establishment has an annual gross volume of sales made or business done in excess of the amount specified in the statute, and analysis will be made at the beginning of each quarter-year so that the employer will know whether or not the dollar volume tests have been met for the purpose of complying with the law in the workweeks ending in the current quarter-year. The total of the gross receipts from all its sales or business during a 12-month period which immediately precedes the quarter-year being tested will be the basis for analysis. When it is necessary to make a determination for enterprises or establishments which are operated on a calendar year basis for income tax or sales or other accounting purposes the quarter-year periods tested will coincide with the calendar quarters (January 1-March 31; April 1-June 30; July 1-September 30; October 1-December 31). On the other hand, where enterprises or establishments are operated on a fiscal year basis, which consists of an annual period different from the calendar year, the four quarters of the fiscal period will be used in lieu of calendar quarters in computing the annual volume. Once either basis has been adopted it must be used in making subsequent calculations. The sales records maintained as a result of the accounting procedures used for tax or other business purposes may be utilized in computing the annual dollar volume provided the same accounting procedure is used consistently and that such procedure accurately reflects the annual volume of sales or business.