For the Proofing Dashboard, how can we get a consistent unit of measurement so to easily track averages?

For the Proofing Dashboard, when we run a report, the metric is reported in hours or days or weeks - we need a consistent unit of measurement so to easily track averages. Turnaround time seems to calculate bizarrely - one week it is in weeks, the next in days. We need to consistency here. Any insight or help appreciated. Thanks!