Effect of rate changes

Except for contracts for the construction of highways, roads, bridges, and buildings, when an unconditional contract to sell tangible personal property is entered into prior to the effective date of a rate change, and the goods are delivered after that date, the new rates are applied to the transaction. When an unconditional contract to sell tangible personal property is entered into prior to the effective date, and the goods are delivered prior to that date, the tax rates in effect for the prior period are applied to the transaction. When a contract to sell tangible personal property contains a specific provision to pass title prior to delivery of the goods, the rates in effect at the time title transfers are applied. Lessors who lease tangible personal property are required to collect tax from their lessees at the rate in effect at the time the lease or rental payment is due, including payments on contracts entered into prior to a rate change. For services covering a period starting before and ending after the effective date of a rate increase, the new rate shall apply to the first billing period starting on or after the effective date. For a rate decrease, the new rate shall apply to bills rendered on or after the effective date.