In the case of an overassessment which arises from the allowance of a deduction for a bad debt or worthless stock which has not been claimed and allowed on a return of the taxpayer for another year, the period of limitation prescribed in R.S. 47:1623 shall be extended for an additional period of two years, and the limitation on the amount of credit or refund provided in R.S. 47:1623 shall be suspended.
La. Revenue and Taxation § 47:264