The vComputer View does extract data from the Item table in regards to the ClientDate, and this date is the date when that resource was first created in that table. This will be the date when the NS agent first sent Basic Inventory after being installed to its managing Notification server. When looking at the View on a Reporting NS, this date will be the first time that inventory date was received from the Forwarding NS.
The Inv_AeX_AC_Identification.[Client Date] column contains the last date and time when either Basic Inventory or Inventory Solution Inventory was received from that resource. This table is an Inventory class and can be forwarded if chosen. Its data will not be changed by the Reporting NS.
The "Altiris Agent installed other than push method" report will only work if the database objects that it uses has been forwarded to the NS. This report uses the vDiscoveredMachines View which is not a member of the DataClass Table.
vDiscoveredMachines uses Inv_AeX_AC_Identification, Inv_AeX_AC_Discovery, Inv_AeX_AC_TCPIP which are Inventory data classes. It also uses the ClientPush Table which is not present in the DataClass table.
The report also uses the Inv_AeX_AC_Client_Agent Table which is an Inventory DataClass, but it also uses the vComputerResource and vComputer Views.
vComputer uses the the Inv_AeX_AC_Identification, Inv_AeX_AC_Primary_User, and Inv_AeX_AC_TCPIP Inventory Tables. It also uses vComputerResource, vItem (replica of Item Table), and vSource (data from Item) Views.
vComputerResource uses the ResourceTypeHeirarchy Table as well as the vActiveAsset View which uses the vResourceHeirarchy View which is a replica of the ResourceTypeHeirarchy Table.
As you can see, the ClientPush Table seems to be the only only able that is not forwarded, which is why this report will fail to function correctly on a reporting NS. This report is only useful if the Reporting NS has managed computers of its own.
The Inventory Forwarding mechanism uses the vInventoryClass View to obtain the list of DataClasses that can be forwarded and will only display those Tables that that have a ClassType=0 value. This view is a replica of the DataClass table.
When you open the Inventory Class list to select which data classes you wish to have forwarded, you can see all DataClasses that can be safely used within reports on the Reporting NS. You can also create your own Views in order to extract the desired data, but at present there is no supported method of adding Tables to the data class forwarding list.
If you still require data from the Forwarding Notification Servers that is not able to be forwarded, then you could use our Connector Solution (which requires a license), or you could use SQL Server Enterprise Manager to extract data from these Notification Servers and then populate Table or Views on the Reporting NS.