WASHINGTON (AP) — Medicare’s new prescription drug plan finder has a glitch that can steer unwitting seniors to coverage that costs much more than they need to pay. The online system automatically displays the plan with the lowest monthly 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.