(a) Each packer purchasing livestock on a carcass grade, carcass weight, or carcass grade and weight basis shall, prior to such purchase, make known to the seller, or to his duly authorized agent, the details of the purchase contract. Such details shall include, when applicable, expected date and place of slaughter, carcass price, condemnation terms, description of the carcass trim, grading to be used, accounting, and any special conditions.

(b) Each packer purchasing livestock on a carcass grade, carcass weight, or carcass grade and weight basis, shall maintain the identity of each seller's livestock and the carcasses therefrom and shall, after determination of the amount of the purchase price, transmit or deliver to the seller, or his duly authorized agent, a true written account of such purchase showing the number, weight, and price of the carcasses of each grade (identifying the grade) and of the ungraded carcasses, an explanation of any condemnations, and any other information affecting final accounting. Packers purchasing livestock on such a basis shall maintain sufficient records to substantiate the settlement of each transaction.

(c) When livestock are purchased by a packer on a carcass weight or carcass grade and weight basis, purchase and settlement therefor shall be on the basis of carcass price. This paragraph does not apply to purchases of livestock by a packer on a guaranteed yield basis.

(d) Settlement and final payment for livestock purchased by a packer on a carcass weight or carcass grade and weight basis shall be on actual hot weights. The hooks, rollers, gambrels or other similar equipment used at a packing establishment in connection with the weighing of carcasses of the same species of livestock shall be uniform in weight. The tare shall include only the weight of such equipment.

(e) Settlement and final payment for livestock purchased by a packer on a USDA carcass grade shall be on an official (final - not preliminary) grade. If settlement and final payment are based upon any grades other than official USDA grades, such other grades shall be set forth in detailed written specifications which shall be made available to the seller or his duly authorized agent. For purposes of settlement and final payment for livestock purchased on a grade or grade and weight basis, carcasses shall be final graded before the close of the second business day following the day the livestock are slaughtered.