It looks like nbd was able to find the problem, which plagued many people (including me) with QoS. You can find details in this thread on OpenWrt forum. Instructions on how to install QoS package can be found in this FAQ entry. Give it a whirl and don’t forget to thank Felix Fietkau (nbd).

QoS was the biggest feature on my "wanted" list. It means now I can produce an OpenWrt GUI (webui) module to deal with it. It coincides well with release of Dojo 0.2.2. But most probably I’ll be using a snapshot because guys added so much new stuff to Dojo preparing for Dojo 0.3 (widget release). Given the stability of OpenWrt GUI Homunculus Alpha release, I may upgrade new release to Beta status.

As far as I know nbd plans to add firewall and QoS support to webif as well, so all you I-swear-by-my-text-browser and JavaScript-is-over-my-dead-body guys will be covered as well.