VATREC12040 - Rounding on invoices and rounding at retailers: Can we require retailers to round up and down?
No. Just as we are reluctant to accept significantly less tax than is collected from consumers, we cannot require a person to account for more tax than the amount provided by the VAT Act 1994. Other accounting options are offered for this reason. But, if it suits a particular retailer to account in this way, rounding (up and down) will provide a fair and reasonable result.