Where identical consumer commodities are offered or exposed for sale at two or more prices within a store, the unit pricing information relating to such multiple priced items shall be calculated and displayed based upon either (a) each price at which the item is offered or exposed for sale or (b) the highest price at which the item is offered or exposed for sale. Where a consumer commodity is unit priced at its highest price only, a statement clearly indicating consumer commodities are available at more than one price and that the unit pricing information is based upon the highest selling price shall be included upon the sign required by subdivision (i) of section 345.3 of this Part.