But nagging doubts persist, leading some to conclude that the prosperity is too good to be true.___ US power grid costs rise, but service slips NEW YORK (AP) â¿¿ America's power grid is like an old car. It gets the job done, even if its performance is slipping. But the repair bills go up every year and experts say only a major overhaul will reverse its decline. An Associated Press analysis of utility spending and reliability nationwide found that electric customers are spending 43 percent more than they did in 2002 to build and maintain local electric infrastructure. Since then, power outages have remained infrequent; but when the lights do go out, it now takes longer to get them back on. Neither the spending nor the reliability trends are dramatic on their own. But experts say the combination is revealing: it suggests that the extra money from electric customers isn't being spent wisely â¿¿ or that utilities aren't investing nearly enough to upgrade fragile equipment that is increasingly threatened by major storms. ___ Martha Stewart denies wrongdoing in Penney deal NEW YORK (AP) â¿¿ Home decor and food guru Martha Stewart testified in court on Tuesday that she did nothing wrong when she signed an agreement to open shops within most of J.C. Penney's stores across the country. Stewart testified in New York state court in a trial over whether the company she founded breached its contract to sell cookware, bedding and other items exclusively at Macy's when she inked the deal with Penney. During three hours of testimony, Stewart, who founded Martha Stewart Living Omnimedia Inc., denied Macy's allegations that she did anything unethical and said she was only looking to expand her brand. In fact, Stewart said it's Macy's that didn't uphold its end of the agreement to try to maximize the potential of her business. She said her brand had grown to about $300 million at Macy's, but the business was now "static" at the department store chain. She said she had hoped the business would exceed $400 million.