84.—(1) Where, in the case of a recoverable overpayment, in consequence of a misrepresentation or failure to disclose a material fact (in either case whether fraudulent or otherwise) as to a person's capital, or an error, other than one to which regulation 81(2) (effect of official error) refers, as to the amount of a person's capital, the overpayment was in respect of a period (“the overpayment period”) of more than 13 benefit weeks, the relevant authority shall, for the purposes only of calculating the amount of that overpayment—
(a)at the end of the first 13 benefit weeks of the overpayment period, treat the amount of that capital as having been reduced by the amount of housing benefit overpaid during those 13 weeks;
(b)at the end of each subsequent period of 13 benefit weeks, if any, of the overpayment period, treat the amount of that capital as having been further reduced by the amount of housing benefit overpaid during the immediately preceding 13 benefit weeks.
(2) Capital shall not be treated as reduced over any period other than 13 benefit weeks or in any circumstances other than those for which paragraph (1) provides.