Looking at the specs, the E80 looks like they took the G70 and packaged it in a 61 key with speaker version. I do see there are 2 expansion slots compared to the G70's one slot and that there are about 90 more factory styles. Almost every other feature looks just like the G70.
The six fill ins are not on dedicated buttons on the G70 so I would think the E80 would be set up the same way. There is an Auto Fill buttons which when lit does a fill when you push variation buttons within the style. You have 4 fill ins when you press from one variation to another. Also, when you go from 1 - 2 and then back from 2 -1, you get a different fill. 3-4 and back also gives you two different fills, so this is how you end up with 6 on the Roland keyboards.
George Kaye
Kaye's Music Scene
Reseda, California