Should the removal of restrictions affect only part of the acreage covered by a lease containing provisions to the effect that the royalties accruing under the lease, where the fee is divided into separate parcels, shall be paid to each owner in the proportion which his acreage bears to the entire acreage covered by the lease, the lessee or assignee of such unrestricted portion will be required to make the reports required by the regulations in this part and the operating regulations with respect to the beginning of drilling operations, completion of wells, and production the same as if the restrictions had not been removed. In the event the unrestricted portion of the leased premises is producing, the owner of the lease thereon will be required to pay the portion of the royalties due the Indian lessor at the time and in the manner specified by the regulations in this part.