Correct, but the performance they're talking about isn't really waterproofness. Or, to put it another way, the goretex fabric itself is waterproof; there's a membrane that will/should not allow water to pass from the outside going in. As a second layer of defense and impressiveness, DWR gets applied to the outside of the fabric. This is what causes the water to bead up on the surface, and roll off. That should be reapplied about once a season, or more often if you wear a backpack, rest against a lot of benches, etc. But the goretex should never let water through, even without DWR; it should just soak into the outer layer of your jacket and be absorbed there, making your jacket heavier, but still leaving you dry on the inside.

I use Granger's on my jackets. For the record, spray on is a better way to apply DWR than wash in, because you really don't want this happening on the inner layer - it's supposed to let sweat out.