I have experienced needing to restart during the running of WPI and it may skip an entry to solve this I would either call a sleep command for like 45 seconds or use numbering and make sure xpize runs last.
With the short leadout option I got about a 730 meg cd burnt. They just can't really hold more than that. This however may help you: http://www.afterdawn.com/news/archive/2881.cfm