if I remember right.
the speedtouch had lower latency then both my billion routers. on top of that there was an occasional random jump in latency that would occur at ppp connect time. The latter issue appears fixed and I think the former is also fixed now with that profile fix you did.
However to save both of us time and effort I stopped using the billion's as they very poor at maintaining sync on tiscali's equipment compared to the speedtouch and it's logical to use the router that can handle the connection best which in my case is my speedtouch 585.