officer could have enhanced the value ." This finding of the Commissioner (Appeals) is perverse as it is clearly contrary to the specific statement made by the importers in the letters submitted by them to the assessing officer. What has also to be kept in mind is that section 17(5) of the Customs Act permits the importers to waive this right. In the present case, as noticed above, the proper officer doubted the truth or accuracy of the value declared by the importers for the reason that contemporaneous data had a significantly higher value. It was open to the importers to require the proper officer to intimate the grounds in writing for doubting the truth or accuracy of the value declared by them and seek a reasonable opportunity of being heard, but they did not do so. On the other hand, the importers submitted in writing that though they had declared the value of the imported goods at a particular value, but on being shown contemporaneous data, they agreed that the value of the goods should be enhanced. When the proper officer has reason to doubt the truth or accuracy of the value declared in relation to any imported goods, he may ask the importer of such goods to furnish further information including documents or other evidence and if, after receiving such further information, or in the absence of a response of such importer, the proper officer still has reasonable doubt about the truth or accuracy of the value so declared, it shall be deemed that the transaction value of such imported goods cannot be determined under the provisions of sub-rule of rule 3. The appellants would contend that the concession which is spoken of in sub-section essentially appears to stand restricted to a reassessment being undertaken by the proper officer and the formation of opinion contemplated under Section or Rule 12 not being questioned. However, that concession would not detract from the right of the importer to question the correctness of the assessment undertaken and which right otherwise stands protected under different provisions of the Act.