Logging in to that character should fix it. Api gets its xml from achievement script that splits big xml to smaller chunks for web services. Initially it did not copy over race info and therefore chars not logged in since the fix do not have race listed.
These should be postcraft values. You need to know min/max value for stat for that item to get absolute value that is showed in game.
Item absolute stat values seems to be caluclated in <code/ryzom/server/src/entities_game_service/game_item_manager /game_item.cpp> file. While it does not list min/max values (those are in server config file), it does show max formula (most is 'min+(max-min)*value => absolute', but not all)
It is unfortunate because all developpers will have to do the same thing in their applications.
@Mjollren some good ideas, I added to my todo list, thanks ;)