Variations in the weight of the wood account for nearly all that weight difference. Mine is nine pounds even but when I bought it from sweetwater they had some listed that weighed nearly 10 pounds and one that was under 9 pounds. I read on TB somewhere that someone purchased the heaviest one they had thinking it would eliminate neck dive. Turns out all the extra weight was in the neck and headstock and it suffered from massive dive. Mine is pretty well balanced, with no dive.
Edit: I just remembered that Eppi has changed up on the VP tuners, so there could be a bit of weight difference there but it wouldn't be much.
Scott had mentioned the new tuners now have tapered posts. Too bad they went that route. Prefer non tapered.