Reconciliation
Reconciliation is the end-of-period process of confirming what was actually delivered and billed against what was planned and ordered, resolving discrepancies, credits and adjustments. Strong pacing during the flight makes reconciliation a confirmation; weak pacing makes it a discovery.
In practice
Reconciliation surfaces the definitional issues - gross versus net, platform corrections, invalid traffic credits - that should have been agreed in the plan.
The most expensive sentence in media operations is 'we found it at reconciliation'. Daily actual-versus-planned monitoring exists to retire it.