It was the best of times, it was the worst of times for companies to dodge taxes by moving to Ireland. So far, results have been mixed for new Treasury Department rules designed to thwart deals known as "tax inversions," in which a U.S. company buys a company in Ireland or some other low-tax locale and moves its headquarters there to cut its tax bill. Banana giant Chiquita on Tuesday stuck by a plan to merge with Irish rival Fyffes and relocate from Charlotte, North Carolina, to Ireland in one such deal.