The owned assets must have both the 'asset' and the 'managed by APM' flags turned ON, for the asset to be considered for reconciliation.
In addition, the asset families must be marked for inclusion in the reconciliation process. To check which asset families will be included in reconciliation, navigate to the Directory -> List management tab, and click on Asset Family. The asset families that will be included in reconciliation have the 'Reconcile Hardware' flag turned ON.