20 CFR §255.13

1. (a)Recovery is considered to be against equity or good conscience if a person, in reliance on payments made to him or her or on notice that payment would be made, relinquished a significant and valuable right (Example 1 of this section) or changed his or her position to his or her substantial detriment (Example 2 of this section).
2. (b)An individual's ability to repay an overpayment is not material to a finding that recovery would be against equity or good conscience but is relevant with respect to the credibility of a claim of detrimental reliance under paragraph (a) of this section.
3. (c)This section may be illustrated by the following examples: