This whole widely variable download speed scenario for different users, irregardless of bandwidth capabilities, leads me to believe that it must be based on your location. Perhaps in my case, Sony's pipeline is wider, or at least the smallest bottleneck is wider (Sony's plus that of your internet provider). Perhaps Sony's pipeline is closer as well. There's no other reason that I should get double the download speed as some others, and if I were to move next door to you, then I would get the same speed as you.
I think I brought this up before, and somebody mentioned another reason, but I forgot it.