I was forced into a 7 nt booking for a booking at 3 mo + 1 week out. The strange thing was that I saw the split week earlier when I did the search, but then the split week option disappeared after I did another search and then came back to this search again (maybe 10 minutes). Only full weeks were showing. I waited 30 minutes and tried different browsers and computers trying to get back that split week option. Finally, I booked the full week. It reappeared the next day (after I booked). This was for a very low season week in a studio, so I took the hit in points and kept the reservation since I didn't want to pay $100 in cancellation and rebooking fees to save those points. I know there were multiple weeks available of the studio unit for this low season week since after I booked the studio, there still was a studio showing available.
This occurrence of not showing a split week also happened another time for a different resort for a 3 bedroom, but I am not so sure there were multiple units of that, but I felt that at 3 months out, I should have been able to have the option to split a week if the full week was available. My conclusion is that the system is messed up but no one really knows. I've complained after the fact, but it doesn't help me since all my timeshare activity happens after the call center is closed and I can't go back and recreate the situation for them.
From what I understood of the old system, unless it's a protected holiday week, if it was available, you should be able to split out that week regardless of how far out you were as long as you were the next person on the wait list/or if it's just out there in the system to be booked.