Never heard that one before, unless you're specifically talking about classical guitar.
Otherwise, all I can say is don't worry about it.
Your wrist and fingers will naturally find the best angles over a period of time.

Classical's a different story. The strings are further apart and there's a lot of chords and stretching involved. The technique is usually leaning more toward keeping your thumb on the back of the neck and keeping a bit of a stiff posture. (just my opinion though... I play classical sometimes but never took any formal training in it)