Workforce and activity are in constant flux and therefore, to some extent always a little out of date. The WRaPT tool is designed to take a snapshot in time, as the goal is to produce long term models rather than operational level reporting.
WRaPT works on annual figures so any seasonal trends will be accounted for. Over the year many small changes would have a minimal impact on modelling outputs but data can be refreshed at any time if large changes to workforce or activity have occurred.