Wait, so by holding a weapon in your off-hand while attacking with the one-handed weapon in your other hand, you incur the TWF penalties, right? And you can ignore those penalties by, say, holding the blade of the weapon in your off-hand, instead of the handle?
Am I the only one who thinks that sounds stupid? Holding a coffee cup doesn't give you TWF penalties, so why should holding a dagger do so? Should your hand be required to be empty or on the handle/haft of the primary weapon?
Why shouldn't the TWF penalties apply only on your turn, while making a full attack and gaining an extra attack? Then, after you've made your full attack, the penalties are no longer applicable, because you're no longer in the midst of that full attack.
There, done, no more confusion. Now, which part of that solution is incorrect?