believe it or not as of now you do not have a leg to stand on in the central office! You have reached the stated speeds both up and down. There could be several determening factors in your problem? as I see it, your looking for consistency and your not going to get it because of the nature of the beast (i.e.) the www. try working with some of the tcp/ip stack tools that are offered at dsl reports and don't worry about your register the values that are default can be replaced,

hard work does payoff
