(a) each month the market administrator shall correct for mathematical and other obvious errors all reports filed pursuant to section 20.30 of this Part, including the pounds of skim milk and butterfat, respectively, in each class in accordance with sections 20.40 through 20.44 of this Part;

(b) if any of the water contained in the milk from which a product is made is removed before the product is utilized or disposed of by a handler, the pounds of skim milk used or disposed of in such product shall be considered to be an amount equivalent to the nonfat milk solids contained in wuch products plus all the water originally associated with such solids;

(c) skim milk and butterfat contained in receipts of bulk concentrated fluids milk and nonfluid milk products that are reconstituted for fluid use shall be assigned to Class I use, up to the reconstituted portion of labeled reconstituted fluid milk products, on a pro rata basis (except for any Class I use of specific concentrated receipts that is established by the handler) prior to any assignments under section 20.45 of this Part. Any remaining skim milk and butterfat in concentrated receipts shall be assigned to uses under section 20.45 of this Part, on a pro rata basis, unless a specific use of such receipts is established by the handler; and

(d) Class III-A milk shall be allocated in combination with Class III milk and the quantity of producer milk eligible to be priced in Class III-A shall be determined by prorating receipts from pool sources to Class III-A use on the basis of the quantity of total receipts of bulk fluid milk products allocated to Class III milk at the plant or unit.