Provisional assessment: enables provisional tax payment with bond for goods or services, followed by finalisation and interest or refund adjustments. Provisional assessment allows a taxable person unable to determine value or tax rate to request provisional tax payment; the proper officer must order provisional payment within ninety days, typically conditioned on a prescribed bond with surety securing payment of any difference. A final assessment must be completed within six months of the provisional order, subject to authorized extensions. Interest is payable by the registered person on unpaid tax from the day after the original due date until actual payment, and interest on any refund arising from the final assessment is payable under the refund provisions.