1.    Before the expiration of time prescribed in section 57-39.2-15 for the assessment of tax, the commissioner and the taxpayer may agree in writing to an extension of time for the assessment of the tax. The tax may be assessed at any time prior to the expiration of the period agreed upon. The period agreed upon may be extended by subsequent agreements in writing made before the expiration of the period previously agreed upon. No extension may be for more than one year from the date of the extension agreement.

2.    If a taxpayer agrees to an extension of time for assessment of tax, the period of time for refund claims will be similarly extended.