No, the power supplies are not a "could use up to" situation. They're complete BS.
Say I'm Belkin... I just made a sick KVMP. Now I need to get the cheapest power adapter supplier for it. My device uses 1 amp. 1 amp supply from manufacturer A costs 40 cents, 2.6 amp supply from manufacturer B costs 36 cents. B gets the sale. Done.
Seriously, measure the KVMP draw with a multimeter. I promise it probably won't even touch 1 amp.
Switching regulators are not huge heat generators. They may get warm but never really hot.