penny: if you have a 1 day turnaround and upload tracking numbers within this time, the buyer doesn't get to rate you on Postage time.

What I am wondering about that is -  does the post within 1 day start from the time the item is sold, or the time the buyer pays for the item?

If buyer doesn't pay till day 2 or 3, then you can't upload tracking numbers within 1 day of sale. I wouldn't create an online postage label until the buyer pays (incase they don't).