I'm not sure it means anything special. If you want it 800 grit, you do it at 800 grit with 4 sides. It's more important that, as a base coat or grit level, you erase all signs of a previous sanding. You may actually want to start with 500 grit depending on the condition of the surface. Then I'd use the 1000 grit pad (fresh one) to make sure you remove all 800 grit sanding lines. I only say this because they did a double sanding with each grit pad.
All things considered, 1000 grit is pretty rough starting point for bowling, for most people.