Retail sale price determination: highest ascertained price applies when declaration is missing or tampered, via market enquiries. Where declaration of retail sale price is missing, obliterated or tampered with, the Assistant or Deputy Commissioner of Central Excise shall ascertain the retail sale price by: adopting a declared price for identical goods removed in a proximate period; conducting sample-based retail market enquiries where the goods are normally sold; or, where declared prices have been increased by tampering, applying the increased price for goods removed within the relevant temporal window. If multiple prices arise, the highest ascertained price applies; otherwise price is ascertained under the rule's general principles.