WASHINGTON (AP) – A glitch in Medicare’s revamped prescription plan finder can steer unwitting seniors to coverage that costs much more than they need to pay. People who help with sign-ups and program experts say it can be confusing – and costly – if consumers aren’t careful. Serving some 60 million Medicare recipients, the plan finder is the most commonly used tool on Medicare.gov and just got its first major update in a decade. The online system automatically displays the plan with the lowest premium. But because of out-of-pocket costs like copays, that’s not necessarily the least expensive plan. The difference can amount to hundreds of dollars. Medicare says it chose to display the premium prominently because it’s a number that consumers understand. Sign-up season for Medicare prescription drug plans ends Dec. 7.