On the top left of the windows the is a drop down. Change that to expert.
Now click on the configure button to open the configure window/menu.
Click on the slots tab , in the slots box click on SMP then on the Edit button in the bottom right
Scroll the window down to the Extra slot options and click the Add button.
A small window will appear.
In Name type client-type
In value tyoe advanced
Then click the OK button on that window, OK on the Slots Window and Save on the configure Window.
Once this has been done it will finish the current work unit and the next one it downloads will be an advenced work unit. These can be bigger or smaller than the 'normal' work units. But in general their PPD is higher.