(a) maintain a main office and such branch offices as may be necessary;

(b) promptly notify a handler, upon receipt of the handler's written request therefor, of the market administrator's determination: as to whether one or more plants exist at a specified location, as to whether any specified item constitutes a part of the handler's plant, or as to which plant a specified item is a part in the event that the particular premises in question constitutes more than one plant: provided, that if the request of the handler is for revision or affirmation of a previous determination, there is set forth in the request a statement of what the handler believes to be the changed conditions which make a new determination necessary. If a handler has been notified in writing of a determination with respect to an establishment operated by him, any revision of such determination shall not be effective prior to the date on which such handler is notified of the revised determination;

(c) place the sums deducted under section 20.61(d) of this Part and retained pursuant to section 20.70 in an interest-bearing account or accounts in a bank or banks duly approved as a Federal depository for such sums or invest them in short-term United States Government securities;

(d) for the purpose of allocating receipts from other Federal order plants under section 20.45(a)(14) of this Part and the corresponding step of section 20.45(b) of this Part, publicly announce the market administrator's estimate of the utilization (to the nearest whole percentage) in each class during the month, of skim milk and butterfat, respectively, in pool milk of all handlers. Such estimate shall be final for such purpose;

(e) report to the market administrator of the other order, as soon as possible after the report of receipts and utilization for the month is received from a handler who has received fluid milk products or bulk fluid cream products from another order plant, the class to which such receipts are allocated pursuant to sections 20.40(c) and 20.45 of this Part on the basis of such report (including any reclassification of inventories of bulk concentrated fluid milk products), and thereafter any change in such allocation required to correct errors disclosed in the verification of such report.