Problem with list of VM's

I have one Datacenter.
When I'm trying to get a list of VM's via API, a get 236 machines.

But WebClient shows me, that there are 243 machines!

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Here is the code I use: (it's sample code from SDK) - C#

private static ObjectContent[] getVMs(ManagedObjectReference dcMoRef)        {            // The PropertySpec object specifies what properties            // retrieve from what type of Managed Object            PropertySpec pSpec = new PropertySpec();            pSpec.type = "VirtualMachine";            pSpec.pathSet = new String[] {                           // "summary.config.instanceUuid",                //"config.locationId",                "config.uuid"            };            pSpec.all = true;            SelectionSpec recurseFolders = new SelectionSpec();            recurseFolders.name = "folder2childEntity";            TraversalSpec folder2childEntity = new TraversalSpec();            folder2childEntity.type = "Folder";            folder2childEntity.path = "childEntity";            folder2childEntity.name = recurseFolders.name;            folder2childEntity.skip = false;            folder2childEntity.skipSpecified = false;            folder2childEntity.selectSet =               new SelectionSpec[] { recurseFolders };            // Traverse from a Datacenter through the 'vmFolder' property            TraversalSpec dc2vmFolder = new TraversalSpec();            dc2vmFolder.type = "Datacenter";            dc2vmFolder.path = "vmFolder";            dc2vmFolder.selectSet =               new SelectionSpec[] { folder2childEntity };            dc2vmFolder.skip = false;            dc2vmFolder.skipSpecified = false;            ObjectSpec oSpec = new ObjectSpec();            oSpec.obj = dcMoRef;            oSpec.skip = false;            oSpec.selectSet = new SelectionSpec[] { dc2vmFolder };            PropertyFilterSpec pfSpec = new PropertyFilterSpec();            pfSpec.propSet = new PropertySpec[] { pSpec };            pfSpec.objectSet =  new ObjectSpec[] { oSpec };            pfSpec.reportMissingObjectsInResults = true;            pfSpec.reportMissingObjectsInResultsSpecified = true;                    return _service.RetrieveProperties(_sic.propertyCollector,                  new PropertyFilterSpec[] { pfSpec });        }

The user is the same... Maybe some VM have a permission to be hidden by api? Or not?

Or I doing something wrong?