Do you mean there are actually item records in the price file, rather than just assigning the price code to the item and letting it work that way? If so, I would say it's working as expected - once you actually create a record for the item, I would assume you want to do somethig different than the standard, so it wouldn't be changed. Kind of like on SO Lines - if you have already changed the Promise Date to something else, changing the date on the header doesn't flow through.