Notwithstanding any other provision of Title 66 RCW or Title 314 WAC, a spirit, beer and wine restaurant licensee who permanently discontinues business for any reason shall dispose of the salable unopened liquor remaining in stock by sale to the board of the items originally purchased from the board. The board will pay the total amount listed in the official price list then in effect, less the spirit, beer and wine restaurant discount and tax exemption expressed as a percent of the total price and the percent of total expenses assigned to the merchandise division to gross sales as reported on the profit and loss statement in the last published annual report of the board. Combined percentages will be rounded up to a whole percent: Provided, however, That in the case of a sale of business with a spirit, beer and wine restaurant licensee, after obtaining the approval of the board and under the supervision of a representative of the board, may sell the entire inventory of liquor to the incoming licensee at a negotiated price.