No, its not bunk. From about 250-400 you'll get negatives that you can make a nice print from. I've shot XP2 at 200-1250 and made good pictures. Its really pretty amazing how much latitude XP2 allows. This latitude is useful for covering exposure errors and can be used creatively if so desired.(posted 8145 days ago)Why anyone would want to rate individual frames differently is beyond me though. As I stated in my first post, rate it at 320 and don't worry too much about missing a little either way. XP2 (or any other film) does not remove the need to think but it does give lots of room for error. For a beginner needing a little help or anyone shooting under trying conditions XP2 is a great film.
To further answer Felix's question, the prints from the mini-lab may be odd colors because most labs will use color paper and probably not filter it exactly right to get every print neutral. When you have custom prints made, XP2 prints beautifully on real B & W paper. Other C41 process films don't work as well for this workflow because they are made to print by machine on color paper and are not very good for printing on real B & W material. Good luck!