In Relux Desktop 2017 you need to go to the emergency area tab and change the minimum here, then it should show in the output correctly.
In earlier version of relux click on the emergency calc surface, right click (or control + B) and go to properties, then change the minimum level from 1 to 0.5
Hope this helps
We did find this a couple of days later after digging through the settings.
I think I was approaching this from the wrong angle by looking for a program default global setting, rather than in individual emg ref plane property.