Blizard launcher game updates taking way too much internet to download

i just tryed to download a cod update and a game update on steam and was unpleasantly suprised that the steam download was going at 6 mb/s, my family way watching tv online so i stopped it and figured that my isp was struggleing (it wasnt) so i paused the cod update and my steam download shot up to 73 mb/s so how is this 10 mb/s launcher cap using almost 65???