Health security cess declarations: officers confirm computations or notify discrepancies, triggering payment of determined and differential cess with interest. Rule 11 requires the proper officer to confirm declarations and determine cess computations within specified periods: fifteen days if no discrepancy and thirty days with a hearing if a discrepancy affecting cess is found; no fresh declaration under rule 9(2) may be filed until confirmation. The registered person is liable to pay the cess determined after confirmation and any differential cess with interest from the date of installation, start of process, or date of relevant parameter change until actual payment.