Listening Ears?

When I ask my daughters to use their listening ears, they often times look at me with a sour type of look but still do as asked.  My son on the other hand will just point to his ears and pretend not to hear me.  He finds it amusing to act as though mom did not say anything. 
Could it be that my son is already acting out in a way that is in one ear and out the other?  It is as though he forgets what was just said or pretends that he does not understand.  Bed time means play time and nap time is a time to sneak around quietly hoping he will not get caught.  Guaranteed my son is two.  But my daughters at his age did not fight me.  They understood nap meant nap and it was a time to lie down peacefully without a fight in their beds.  To this day, my daughters do not fight me when it is bed time.  My youngest daughter, who is now four does not fight me.  Never has.  Why does my son? 
I feel as though I am sometimes losing the battle of power where my son is involved.  I feel drained when trying to discipline.  I can time out him all I want, but it does not seem to work. 
Although I maintain the discipline methods of time outs, presently they do not work.  I keep telling myself to stay persistant.  But what two year old is going to stay sitting where told?  When he goes for time outs, he slowly starts to slide of the couch and then takes a mad run down the hall way....as though he is going to fly away like superman and rid his mom from taking him back to that "awful" time out spot.
Ugh.  Maybe once the terrible twos fade away, and he gets older things will turn out differently.  But when I look at my step son, I think not.  For what I have seen so far, my girls think they can win someone over with love and large sad eyes.  My son and step son think it is with pure boyish attitude that they are the toughest.  And remember, my girls and my son have all been raised the same.  My step son has been raised in a different home by his mother, and acted the same as my son does now.  Ugh am I in for an interesting thrill ride in the life of parenting opposite genders.  Maybe when he is three, four, five, or six...then his listening ears might kick in.  Until then, at least I have my girls to not drive me crazy.  :)