How to use a IIF with a Lookup expression in SSRS

I have the main dataset named: A, and I need to grab a Percentage column value from dataset named: B but only where the inspection column from dataset B equals "VC". Reminder both the Percentage and Inspection are in dataset B which is different from the main dataset A. Both datasets have a linked/joined column called PhaseTrackingID.

This is what I have currently and it's only returning Nothing:

=IIF( Lookup(Fields!PhaseMaintTrackingId.Value, Fields!FK_PhaseMaintTrackingId.Value, Fields!Insp.Value, "Perc_Comp_By_Phase_INSP_Type") = "VC" And Lookup(Fields!PhaseMaintTrackingId.Value, Fields!FK_PhaseMaintTrackingId.Value, Fields!PhaseInspDesc.Value, "Perc_Comp_By_Phase_INSP_Type") = "INTERMEDIATE 12MO", Lookup(Fields!PhaseMaintTrackingId.Value, Fields!FK_PhaseMaintTrackingId.Value, Fields!percentComplete.Value, "Perc_Comp_By_Phase_INSP_Type"), Nothing )

One part of my problem is that I realize that lookup only return the first value which isn't "VC" so returns false.

Any help will be greatly appreciated!

You can use an expression combining the two columns for your lookup.

=Lookup(Cstr(Fields!PhaseTrackingId.Value) + "VC", Cstr(Fields!PhaseTrackingId.Value) + Fields!Inspection.Value,   Fields!Percentage.Value, "dsB")