The same rules(Modeling Single Parts) also apply to assemblies:

If several individual parts are used, each with classified "CNS_CP" (formerly "RVT_CP" [Revit Family Template Mapping point] in the eCATALOGsolutions classification "CNS"), the first part in the assembly structure (which contains the "CNS_CP" classified point) is usually used for the placement of the assembly.

The order of the parts in the assembly structure is usually kept, subject to optimizations on the system (on-premises PARTsolutions installations / PARTcommunity CAD backend).

	Note
	Modeling has to make sure that there is only one part in assemblies that contains the connection point for placement (CNS_CP). The connection point should not be on the dummy project, as this is not exported, but on the first "real" component or a part that is available in the assembly in all variants.