Right to appeal to Commissioner (Appeals) against assessment, penalty or rectification with prescribed form, fee and time limits. Appeals to the Commissioner (Appeals) lie against assessments, denial of liability, penalties, rectification orders affecting assessment or refund, and refusals of rectification claims; appeals must be in the prescribed form with fee and within thirty days of service or intimation, subject to possible condonation of delay for sufficient cause up to one year, and the Commissioner (Appeals) may pass orders including enhancements only after affording a reasonable opportunity to be heard.