Part of the reason that Magi use names different from their "true" names is the (Mythic Europe historical) belief that knowing a person's true name gives you power over them.
It is certainly useful in improving Penetration.
Out of curiosity, could you also have a Special Circumstance - (invoking the target's True Name)?
I would use a different term than True Name as that has a mechanical meaning for certain spiritual and other beings with might that is not the same as a human’s original given name.
EDIT: True Names are described in RoP:I, The Cradle & The Crescent, and, I believe, RoP:M if not elsewhere.
There is also a true name theme in Ancient Magic (p:10) in the form of The Language of Adam.
Apparently whenever I read AM5 p84, in the Sympathetic Connections panel, whenever they say about using a particular type of name as a sympathetic connection, somehow I am including "true name". Sorry.
Perhaps I should have written Special Circumstance (invoking a sympathetic connection name)
Either seems reasonable (compare with "while touching the target"), and with the right "mythic feel"!
Ursula Le Guin would approve. 
As a “special circumstance” that you explicitly define as the original name of a human or the true name of those things who have them I think it works fine but in discussing the rules on a forum I think it’s important to make the distinction.