Virtual Keyfigures, e.g. 0AGE_VC (HR content for infocube 0PAPA_C02)

Hello BEx fans

I have a question regarding the virtual keyfigure 0AGE_VC.

In [SAP Help|http://help.sap.com/saphelp_nw04/helpdata/en/3b/fd5ac745a75f42b72f6244307b10c3/content.htm] the following is described:

Technical name: 0AGE_VC

Use

Personnel Administration: This key figure contains the headcount change for age in years. It is always initial because the headcount key figure 0AGE_NC belonging to it is implemented as a virtual key figure.

Does it mean, that 0AGE_VC will never be calculated and that 0AGE_NC is the "real" virtual keyfigure?

What is the purpose of this virtual keyfigure 0AGE_VC

thanks

BEO