I guess the way I deal with this is to charge separately.  For instance, things like insurance pay unavoidable commissions and that is disclosed at the beginning.

In short, every client pays either a commission or a fee on everything they use, but never neither and never both simultaneously. 

To me, this is more a matter of itemized compartmentalization with disclsoure rather than "value added".  I personally think the idea of 'value added' is a bit nebulous.  I'd rather add the service into an all-encompassing price/ value propostion – accepting that some services will be de facto loss leaders.