Yes it should but this has never been done.
I think that the reason is :
Most telcom providers do no want to see this inside IP protocols, because they want to keep their ATM hardware and links as long as possible.
The furur is IP, not ATM. We need a strong QOS inside IP now. We need a reliable fragmentation mecanism between WAN routers.
Without this, even HFSC is not strong enough to give the same level of jitter than ATM on slow links.