If a local educational agency or a private elementary or secondary school that has violated this subchapter proves to the satisfaction of the court that the agency, school, or department had reasonable grounds for believing that the underlying act or omission was not a violation of this subchapter, such court may, in the discretion of the court, reduce the amount of the liability provided for under section
2617
(a)(1)(A) of this title to the amount and interest determined under clauses (i) and (ii), respectively, of such section.