I also inherited a system and the value was 25%.  I had a schedule and it's
startt was 20:00 and
the durh=12 and the previous event completed around 18:30. The schedule
would never started at 20:00.  Each time I reviewed the dsmsched.log, the
estimated startt was 3+ hours after the schedule startt. The randomization%
time durh (25%x12) gives the estimated schedule startt I believe.  After
setting the value to 0 (zero), the schedule starts at 20:00.