Users always require setting the working plane height for a proper and compliable daylight simulation result.
We often find users applying for a daylight contour map after they are done with the simulation. The contour and the Lux value at certain points of a room depends on the area of opening and the point of analysis which is largely effected by the working plane height.
To set up the workplane at a desired height, you will need to change the default settings of the Daylighting dialog box.
From this, Radiance would consider the height of daylight matrix as the one specified there.
For a better view, we can also set the view at the same height of a daylight matrix or the workplane height, by adding the View Point as shown below:
To show the simulated result with contours, please refer to the wiki article here.