@MagicValleyHPV, the current should be less, unless that's a linear regulator...
also, the current should decrease as the voltage delivered to the laptop is increased. however the watts will probably increase, the difference in power dumped entirely into the buck regulators, and thus wasted as heat.
if you decrease the voltage and the watts decrease, that would not supprise me either, and there's nothing wrong with running it at a reduced voltage permanently.
most laptops take that 18-21v and imediately convert it to just above the battery voltage. there's a dc-dc converter to charge the battery off that bus, and a dc-dc converter to run the processor, ram, 3.3v, 5v, 12v, etc. there's generally at least 7 of them or so.
its not uncommon to see a significantly reduced power draw by running the laptop off the batteries, with them directly connected to sometype of power supply. (be carefull with that, no short circuit protection...)