I don't believe they have a Remaining Hours field (like MS Project and other tools) at least not one that helps recalculate the duration to adjust for inflight tasks. Obviously you can create one in a form, but it also won't recalculate your dates, etc. This is a sore spot for me when we bought Workfront. We learned to live without it, but it'd be great to have it. Does anyone know of a feature request we can upvote?