welp, its not power draw.  channel 1 is the usb +5v, channel 2 is the PSU +5v;  two boots in succession, one without, one with the unicomp UB404LA.  output range is same as usb 1&2's permitted voltage levels, 4.75~5.25v

it only drew down the +5v usb by .01v in standby, which you can see midway through the log. when powered on, absolutely no change in voltage, 4.905v both times.   there is a voltage dip on initial power on, but still well within spec.