i had the same question for TD-W8901N but no one bothered to answer....after some mystifying researches with no straight answer i have a hunch that there is no such an option as precise traffic shaping on modem routers!!....i found out that this option is always available for non modem routers (which tend to have a different firmware with green interface) but never saw it on our orange interfaced firmware...the only option i found available for modem routers is a basic version of QoS which i think what it only does is setting preference between users (and programs i guess like gaming!!) so for instance if you're online gaming on a game that demand high speeds and your brother is on the wifi you can set it to give the higher speed priority for online gaming...but after testing i don't find it efficient in any way!!

Thank you very much for the answer, very clarifying and frustrating at the same time. So this is a clear case of false advertising cause if you search in the official pages it shows that option exists, like in the link I posted. So I just wasted 50bucks I guess... because its completely useless a router without bandwidth control in a house with 2 or more devices connected.

exactly!!!....i have about the same case you have and i also thought as you did that modem routers are the whole package...i mean why would any idiot want to buy a router then connect it to a modem...well now i know why!!