An asset being imported is a potential asset, which is yet not a part of the asset system. It is the asset that is collected from the data collector but can only be called the asset when it passes through the reconciliation rules. After the reconciliation rules are applied, the asset to be imported becomes an asset.
In this case, the Windows Machines remain the 'asset being imported' until the rule verifies that the computers are not present in the asset system and adds those into the asset system. The Windows Machines that are already present in the system are not added to the asset system and do not become assets.