Effective April 23, 2010, the Washington Department of Revenue has amended a rule that provides specific guidance for the effect of sales tax rate changes for persons performing retail services such as repairing property and construction buildings. The amended rule includes guidance on contracts, sales agreements, and installment sales made prior to the effective date of the rate change. A sales and use tax rate increase applies to the first billing period starting on or after the effective date of the increase, and a sales and use tax decrease applies to bills rendered on or after the effective date of the decrease. Furthermore, the requirement that taxpayers filing returns on a cash basis must make an accounts receivable adjustments at the time of a rate changes has been removed. Additional regulations may apply. (WAC 458-20-235, Washington Department of Revenue, effective April 23, 2010)