No, but the simulation will be completed at 15 and the other 15 won't do anything.  What you need to do is clear out the previous simulation.  To do that reset the end frame to 1 (it will ask you if you want to delete those, say yes.  Then, enter 30, go to 30 and repose your figure.  Then go back to 1 and rerun your simulation.

The reason for going to 30 instead of 15 is that it does a better job of removing the crack and other adjustments that needed to refined.  Thirty appears to be a good number of frames for Poser to resolve shaping and conforming issues.  Some folks go to 100 frames to do it.  Jan