The federal government may be paying hospitals $5 billion too much as a result of an 18-month moratorium on enforcement of rules that tell hospitals when patients should be admitted, says an independent Medicare auditing company. Last September, Medicare officials announced that patients whose doctors expect them to stay in the hospital through two midnights or longer should be admitted, while those expected to stay for less time should be kept for observation. But then Medicare announced a moratorium on penalizing hospitals that violate the controversial rules. Congress has extended the moratorium through March 2015.