That's because the DC-DC's buck converters are still running to provide 5VSB, in case it is needed.
This happens to all DC-DC boards and power supplies unless you shut down the power with a power sequencer. Not a good idea to draw 160ma for more than few days, you can kill your battery.
P.S. Also, the power supervisior on your EPIA board consumes power, but not as much.
Originally Posted by ciagon