The quantities of bottled beer removed subject to tax shall be computed to 5 decimal places in accordance with the table and instructions in Sec. 25.158. The sum of the quantities computed for any one day will be rounded to 2 decimal places and the tax will be calculated and paid on the rounded sum. (Sec. 201, Pub. L. 85-859, 72 Stat. 1333, as amended (26 U.S.C. 5051))