Really? Because my book says, "Any time you draw blood in close personal combat--with your claws or your teeth--you can ingest some of it to gain sustenance." And as I said before, the +1 bonus you get is specific to attacking the target you drank some of.
It is more of a "I have tasted you and have taken some of your power into me, so now I can better anticipate you."
The thing about smelling blood is actually the THIRD effect of Blood Drinker (Blood Frenzy).