Provisional assessment allows provisional tax payment subject to a bond and later final assessment with interest. 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, and provisional payment requires execution of a bond securing payment of any difference. The proper officer must complete final assessment within six months, subject to specified extensions, and the registered person owes interest on unpaid tax from the due date until actual payment; refund interest follows applicable refund provisions.