If you are running a version of Remedy that is older than 9.1 SP3 you may notice the following join condition in the view definition of AST:Base Element when you open it in Developer Studio:
($ReconciliationIdentity$ = 'ReconciliationIdentity') OR ('ReconciliationIdentity' = $Instanceid$)
AST:Base Element is a joing of BMC:Base Element and AST:Attributes.
The first part of the join condition returns reconciled CIs while the second part, in italicized red above, returns unreconciled assets.
The OR condition needs to be removed from the view definition. This issue was addressed in BMC's software defect SW00511666 and fixed in 9.1 SP3.
If your upgrade to 9.1 SP3, or higher, is not imminent you can safely remove the above condition in Developer Studio.