For a construction schedule, better accuracy (by the way of the correct progressing of activities and the calculation of the forecast completion dates) can be achieved by manually entering forecast completion dates (these either to be calculated by the planner/ scheduler or given to him by the relevant person involved in the supervision of the given works).
So two sets of data would need to be fed to the schedule: both “Physical” % complete, and forecast completion dates.
Otherwise, to use the “Duration” % complete will lead to wrong forecast dates. If still in doubt, let us just think of how many times we’ve seen activities with say 95+% complete for weeks and weeks, with the forecast completion date sliding on every single schedule update? The activity’s physical progress might truly be as stated e.g. 95+%, however the last 5% can take anything from 5% to potentially 100% (or more!) of the original activity’s duration.