Claimants desiring to do so will be permitted to elect to combine wages under the terms of any plan for combining wage credits, of which Maryland is a cooperating member. All claims filed under the basic plan for combining wages shall be filed in accordance with the laws of the paying state under the terms of any Interstate Arrangement for the Combining of Wages to which Maryland is a party. All claims for benefits filed under the Extended Plan for Combining Wages shall be filed as follows: If claims are filed in other than the paying state, the Interstate Benefit Payment Procedure shall be followed. If claims are filed in the paying state, they shall be filed in the same manner as by any other claimant who is claiming benefits under the unemployment insurance law of that paying state.