Sum the budget lines for the task (in addition to for the week). When setting up a budget for a project it isn't always as easy as knowing you need X hours each week for 5 weeks. Sometimes it is a few hours here an there. I would think you could add the task sum to the (I) info panel on the right. If you click in the task and click the info panel then it would sum that task for all the weeks. Maybe if you then clicked the top task it would show the total for the whole project.