American Express Membership Rewards - Authorization Codes

Does anyone know if there is some significance to the authorization code received when you use your Amex card?

I've noticed the codes are all 2 digits in the 16 to 33 range. Is there any meaning to them?

http://www.flyertalk.com/forum/Forum69/HTML/001202.html

i'm interested in the answer to this question. unfortunately this post is very old and the link referenced by the above poster no longer works. :(

why are some auth codes 2 digits, 6 digits, or even alpha numeric?

the code and the account number serve as check digits to certify the transaction. Match this to the transaction number and you have a transaction.

the code and the account number serve as check digits to certify the transaction. Match this to the transaction number and you have a transaction.

so are the auth codes random? sometimes, i'll get a 2 digit code.. sometimes i'll get a 6 digit code. back to my original question: does it have any significance?