On Actiontec T3200M
Not sure at 100% but enable SmartSteering disable MAC Address Control.
So your router no more filter device with MAC. So for me SmartSteering is usefulness.
Also if before you have many MAC address in option "MAC Address Control", and you Enable SmartSteering, and decide later to disable it and return to MAC Address Control, all your MAC are lose.
So you need again to enter one by one.
But if you go again at SmartSteering option and you Enable it again, there you will see all your MAC.
But like I say it's usefulnesse since the Router don't care now of this list.
I try with my iPhone.
When SmartSteering Enable and I not enter the MAC address of my iPhone, I can go on the internet with it.
But if I disable SmartSteering and Enable MAC Address Control, this time I can't connect on the Internet.
Just normal since I don't enter again the MAC Address.
You cannot use SmartSteering AND MAC address control. I get a popup when I go to that page stating "Wireless MAC Authentication is not available because the SmartSteering function is active."
You can configure steering based on MAC address under the SmartSteering configuration page but I suspect that's not what you are looking for.