Project uses your baseline plan to make the calculations, which should be the perfect budget since you estimated work, materials, and costs on a task-by-task basis.

You may have read about Budget Resources, which can be created if desired for the sake of comparison. If you are inclined to do so, create the resources (check the Budget checkbox). Assign the budget resources to the project summary task, and then enter the amounts. You can enter the amounts in either Task Usage or Resource Usage Views, but you will have to insert the fields Budget Work and Budget Cost.


Regarding "Also, it seems like "actual duration" and "% work completed follow each other": Yes. The variables Work and Duration are definitely are linked together.