The effective date for restoring benefits that were underpaid (including erroneous collections of overpayments) or denied or closed in error is set as follows:
Except as provided in subsections (b) and (c) of this section, in all programs except the SNAP program, for underpayments resulting from administrative error, the effective date is the date the error was made.
In all programs except as provided in subsection (c) of this section, benefits may be restored only for the preceding 12 months.
When subsection (a) of this section does not apply:
The first of the month after the suspension, if suspension was for only one month; or
The date the benefit group again becomes eligible, if benefits have been suspended for more than 30 days. The Department treats the month in which benefits are restored as an initial month (see OAR 461-001-0000 (Definitions for Chapter 461)).