Driver set up

[TriggerTech]

So, playing around at the range last night, usually on my driver set, at address, my hands are level to my belt buckle, tried standing more upright with my hands above ally button, and found i was hitting alot straighter and gaining 30 yards. Just looking for some advise, ie should my hands remain low (as I would set up with irons or is a more upright stance better? I know it sounds odd!
Cheers in advance