The tax imposed under this chapter is due and payable at the time the deed, instrument or writing effecting a transfer subject to the tax is delivered, and is delinquent if unpaid at the time of recordation thereof. In the event that the tax is not paid prior to becoming delinquent, a delinquency penalty of fifteen percent of the amount of tax shall accrue. In the event a portion of the tax is unpaid prior to becoming delinquent, the penalty shall only accrues as to the portion remaining unpaid. An additional penalty of twenty percent shall accrue if the tax remains unpaid on the ninetieth day following the date of the original delinquency. Interest shall accrue at the rate of one percent a month, or fraction thereof, on the amount of tax, exclusive of penalties, from the date the tax becomes delinquent to the date of payment. Interest and penalty accrued shall become part of the tax. (Ord. 566 § 2 (part), 1994).