Burlington Coat Factory Warehouse Corp. said it would modify its low-price ad claim following an investigation by the National Advertising Division of the Council of Better Business Bureaus. A complaint was brought by the BBB of Western Pennsylvania, citing the claim: "We check the competition daily. So when you check us out, you can be sure you're getting the lowest possible prices." NAD said it was impressed by Burlington's system for checking competitors' prices and responding, but said the unqualified pricing claim was too broad. The off-price retailer's agency is Norman J. Steven Advertising, South Orange, N.J.