Hi J Peters Jr,
As Michael mentioned above, you need to make sure your track rule is setup for percent. Look for the sentence that begins with <GradientValue To set the track rule up to use percent your sentence should look like this:
<GradientValue d:type="cDeltaString">Percent</GradientValue>
After you've updated your track rule, you can then set your gradient values in the following window in the World Editor:

The above bottom left flyout window will only appear when you select the track icon in the top left fly-out. Another tip, when you use the gradient tool (two sided triangle looking gizmo in the top left fly-out ) in the World Editor, make sure you pin both sides of the grade you are adjusting with additional gradient markers or you could end up raising or lowering all the track from the point you are working on up to the end of your track. It's also a good idea to pin all sides of a switch when adjusting grades with the manual gradient tool.
Regards,
Rich S.