(a) The warehouse entry account of the plant designated in the withdrawal to receive credit for the exportation shall be credited with the following:

(1) The quantity of dutiable metal exported.

(2) The wastage in effect on the date of entry at the plant of initial treatment of such materials.

(3) The proportion of any other dutiable metals in the importation being credited which were lost at the said plant in the production of a quantity of dutiable metal equal to that exported.

(b) If credit is being applied to a charge set up by a theoretical transfer under §19.24 at the plant designated in the withdrawal to receive the credit, the wastages to be applied shall be those set up at such plant in connection with the theoretical transfer, irrespective of the date of the withdrawal.

(c) On the transfer of dutiable metal to a bonded storage warehouse, credit shall be applied at the plant designated in the withdrawal to receive the credit in the manner provided for in paragraph (a) of this section with respect to withdrawals for exportation. The charge so credited at the plant shall be set up on the warehouse entry account of the storage warehouse to which the dutiable metal has been transferred. In the case of the withdrawal of dutiable metal for transfer to a bonded manufacturing warehouse, credit shall be applied in the same manner at the plant designated in the withdrawal to receive the credit, but the charge set upon the warehouse entry account of the bonded manufacturing warehouse shall be limited to the quantity of dutiable metal transferred to such warehouse.