Maximum retail price

MRP is a seperate valuation section under sec 4A of central excise act. 

if at the time of import the MRP is not applied, then the person who fixes the stickers on the goods is deemed manufacturer, and would be liable to pay the duty.

ii. Additional customs duty

This is equal to the Central Excise duty leviable on the product manufactured in India and if the said product is not manufactured in India then on like product manufactured in India.

Proviso to section 3(2) of the Customs Tariff Act provides that

(a) where the imported goods are notified under section 4A of Central Excise Act, and

(b) in relation to the goods on which the MRP is required to be printed either under the provisions of Standards of Weights & Measures Act, or the rules made thereunder, or under any other law

then in such case the value of imported goods shall be deemed to be the retail price declared on the imported article less abatement allowed as per the notification issued under sub-section (2) of section 4A of Central Excise Act. As per the proviso to section 3(2) of the Custom Tariff Act in case of an article imported into India for which tariff value has been fixed under section 3(2) of the Central Excise Tariff Act, the value for the purpose of computing CVD would be deemed to be tariff value.

https://wirc-icai.org/wirc_referencer/indirect%20tax/Customs%20Act.htm