Andrea Staub, a spokeswoman for KeySpan, confirmed that it had received a copy of the draft audit last week but added that the company needed time to review it before anyone could comment on it. But she said that some of what the audit called overcharges were in fact debatable contractual issues related to whether KeySpan or LIPA should pick up the cost of managing the electric grid. KeySpan charged LIPA $22 million for that service.