"Netflix can sign usage quota agreements but QFX can't ?" This...

"Netflix can sign usage quota agreements but QFX can't ?"

This is because Netflix pays for its own connections to ISPs. Since ISPs get the data for free, they don't have to charge for it. From http://blog.streamingmedia.com/2014/02/heres-comcast-netflix-deal-structured-numbers.html :

From a technical level, Netflix has their own servers that are sitting inside third-party colocation facilities in multiple locations. To connect Netflix’s servers to ISPs, Netflix buys transit from multiple providers, which then connect their networks to the ISPs. Netflix pays the transit providers for those connections and with that, gets a certain level of capacity from the transit provider.

QFX could do that if they wanted to and could afford to.