I'm at work right now so I can't say. But the menu I'm talking about is just "change pattern after" and then you can select PLEN or any number of 1/16 notes. What additional setting needs to be changed in order to enable this behavior?
EDIT: I looked it up in the manual, and I'm talking about the Project level setting. In the Pattern setting, I never touch the USE PRJ SET. I assume the default is "on", right? If so, shouldn't that make every pattern work the same way as whatever is set in the Project?