We have a new feature in 2015 SR2 to support repeated offset pattern for Stacked plot.
You can select all data and choose Plot: Y-offset/Waterfall: Stacked Lines by Y Offset. Then in Plot Details dialog, choose Layer1 on left panel. Select Stack tab on right panel. Choose Constant and enter e.g. 0 0 0 10 so So the offset will be 0 0 0 0 10 10 10 10 20 20 20 20 ....
To do it in 8.5.1, you may need some script to loop through all plots and set each plot's offsets.