Yup it does. Its one of the reasons I hate UPS ground. Seems to take forever and they typically dont deliver on Saturdays. I dont think its available for ground though, only like 3 day air or whatever other services they offer.
According to my shipping people here at work, Fedex ground tends to deliver on Saturdays for residential deliveries, but NOT on Monday. UPS doesn't deliver on Saturdays, unless you pay for Saturday delivery, which is of course, more expensive.
We typically send more packages by 2nd Day Air, and that is 2 business days, and doesn't include weekends or holidays. Same for ground packages. Our UPS and Fedex drivers can arrive any time between 8am to 8pm. Hope this helps a little bit!