129P.— (1) This section applies if—

(a) a BID levypayer has paid the BID contribution levy payable in respect of a rateable property for a chargeable period,

(b) the valuation of the property changes during that chargeable period because of amendment to the valuation list described in section 28 of the Valuation Act 2001, and

(c) the BID levypayer has not received a refund or credit under section 129O in respect of the rateable property for that chargeable period.

(2) As soon as reasonably practicable after amendment of the valuation of the rateable property described in subsection (1), the BID contribution levy for that rateable property shall be recalculated by the rating authority under section 129N(2) or (3), as the case may be, using the same BID multiplier but the amended valuation for the property, and the recalculated amount shall be prorated based on the number of days remaining in the relevant chargeable period, beginning with the date that the valuation is amended.

(3) If, as a result of the recalculation under subsection (2), the payment of the BID contribution levy described in subsection (1)(a) involved an overpayment and there are no arrears of BID contribution levies outstanding on the property concerned or if there are such arrears they are less than the amount of the overpayment, then the rating authority shall pay to the BID levypayer concerned a refund in the amount of the overpayment less the amount of any such arrears owing.

(4) If, as a result of the recalculation under subsection (2), the payment of the BID contribution levy described in subsection (1)(a) involved an underpayment, then—

(a) the BID levypayer is liable for the balance owing,

(b) the balance owing may be recovered from the BID levypayer by the same means provided under section 129N, and

(c) the provisions of section 129N(4) to (9) apply for the purposes of that recovery.

(5) If—

(a) the amended valuation for the rateable property referred to in subsection (2) is consequently the subject of an appeal under Part 7 of the Valuation Act 2001, and

(b) after all appeals under that Part have been exhausted, the final valuation of the property for the relevant chargeable period is different than it was for purposes of the recalculation under subsection (2),

the rating authority shall recalculate the BID contribution levy for that property under section 129N(2) or (3), as the case may be, using the same formula applied in those provisions except where "B" is now the final valuation of the property referred to in paragraph (b) of this subsection.

(6) If, as a result of recalculation under subsection (5), the amount of money paid by the BID levypayer for the relevant chargeable period involved an overpayment or an underpayment, then—

(a) in the case of an overpayment, subsection (3) applies, and

(b) in the case of an underpayment, subsection (4) applies.]