There is no circular or clarification on this aspect. The question that is to be decided before come to a conclusion is that
whether the practice adopted by you that paying first on the previous year cost and in case of increase in the final costing for the current year paying differential duty with interest (which is in the knowledge of the Department) accepted by the Department or not.
If it is accepted , then there is no question of paying penalty.
Otherwise, you have no option to opt for provisional assessment.
I want to share with you a situation where the assessee first opted for provisional assessment for all his units and paying regularly the differential duty with interest wherever there is increase in the final cost. Having observed that this is a revenue neutral situation, the Department issued us a letter to simply pay the differential duty with interest in case of increase in the cost without continuing under provisional assessment. And the said assessee is still continuing the same practice
In view of this you may have to take a call accordingly.
Best Regards
Suryanarayana