Scepter range is borked
This is most likely not a bug, but intentional. I observed the same with other projectiles (like ranger ones). The attack range is 900 (for scepter) but the projectile travel a bit further than that. It’s an unreliable increase of projectile range, but not attack range. Be happy about that.
This doesn’t work for the GS, since it doesn’t use projectiles.
And I believe it also doesn’t work with Staff, because it uses “distance limited” projectiles. After 1200 they disappear. If used <1200, they bounce up to an accumulated distance of 1200.