When you subtract the 18mA difference between the two circuits "being the relay", amount of difference in efficiency can be shown.

  This chart shows regulator's amount of current use over the switcher.
current-diff.jpegThe following data is overall load, without minus current use of the relay.
317compare2575.jpeg

The switcher is more efficient at using only what the motor needs, as it requires more, the faster it is trying to spin the load.