When I worked at one the customers package would arrive at the ups store the same day it was due for delivery to their home. It kind of depends on the drivers route if the package would arrive at the store earlier in the day or at the same time they picked up the ground packages from the store(usually an hour or two before closing). They get scanned into the stores computer and you get notified plus your tracking status changes to let the customer know its at the ups store. If for some reason it arrives later in the day Friday you should definitely be able to pick it up Saturday from the UPS store. I think its kind of a computer glitch people get since weekends aren't considered delivery days at UPS
Someone asked earlier about the address on their ID not matching the delivery address. Is the info I got correct in that you can bring a utility bill, or a copy of your lease with your ID as proof that you are who you say you are?