try this as it relates to the rating issue.
As for AS there are diferent codes. 5002 for the general diagnosis..which got me a whopping 20%. Then there is 5029 (someone correct me if I'm wrong) for the active process and how it effects the joints. This should use the diluca criteria for measuring limited rang of motion.
Get a complete up to date copy of your husbands civilian medical records and get then to the person handling the claim. Your doctors office should not charge for the copy since it is for the VA.
If there are no measurements in his records to show limited mobility ask for an appointment to get the measurements...although we all know AS has good days and bad and the measurements change.
I'll check back in later this afternoon/evening.