If they are pointing to different materials I would think this would work. It shouldn't matter what order each script runs because when it does run it moves to pivot 1, takes a snapshot, paints to material 1, then moves back. Then when the next one runs it does the same thing but to that pivot's location and that material. The snapshot is what you're after and assigning to the material right?
Shadmar, are you creating a new buffer in each script? If not can you do that?