Jump:
If the character intentionally jumps down from a height, the character might take less damage than if the character just fell. If the character succeeds at a Jump check (DC 15), the character takes damage as if the character had fallen 10 feet less than the character actually did.
Tumble:
DC15 - Treat a fall as if it were 10 feet shorter when determining damage.
So, what if you have the Jump and Tumble skills AND choose to jump from 30ft up? What damage do you take? Can you make both difficulty checks and reduce damage to 1d6?