669;
You are in what I'm going to call "the bounce" 
And you actually spotted it. It happened to me too. It's when you have a backdating AMEX reporting, not as new, but hasn't been calculated by the scoring system for AAoA yet.
Freaked me out when for a couple days or so my score did just EXACTLY the opposite of what I expected it to do after adding a TON of AAoA with back dating. After scoring systems corrected, my score shot back up along with my AAoA changing (for the longer). I don't know why it happens but it often if not usually does and most people don't spot it or the move doesn't trigger a SW alert and they don't check.
Maybe it happens because it's something unique to AMEX and none of the scoring systems are "instant auto" to deal with it, would be my guess.
@669 wrote:Ryvision
That makes a lot of sense..On the new report my AAoA did not move.
How long did it take for the CB to correct?
I was a little aggravated last nigh since I had in the back of my mind that adding the AMX with 23 years backdating and the additional $5100.00 CL could only give me a boost.
This was on the report, I should have figured it out:
Changes to your credit report
Your FICO® score went down on a day when there were no credit alerts on your Equifax Credit Report™. This can happen if:
- There was a change on your credit report that lowered your score but did not trigger an alert. For example, the balance on an account might have increased enough to lower your score, but not enough to trigger a balance increase alert.
- You moved from one category of credit users to another as time passed. For example, you may have transitioned from the category "consumers with a new credit history" to the category "consumers with a two- to five-year credit history". As a result, your credit report is evaluated differently, causing a slight change in your score. The good news is that moving between categories like this usually offers you the potential to reach a higher FICO® score in the future.
I will continue to monitor and post what happens.
Thanks Ryvision, I feel better
It was last year but I seem to recall it as being just a few days to maybe a week (that would be at the very outside). At first my scores (all) dropped, 10's of points, each CB doing so as the new AMEX hit. Of course I thought "oh K-RAP what went wrong!?" and I couldn't find anything other than the new AMEX being the cause (same as you) then later, BANG AAoA went up (none did the same reporting day that I remember) and BOOM 40 to 60 points added to each CR! Fakos included. It was the sigh of relief heard around, well.... the room
I'm guessing it may do the same thing again when the new AMEX Blue hits, but at least this time I'm somewhat prepared for it
Oh btw, welcome to, or welcome BACK to the 1989 AMEX Family 
Ryvision wrote:
It was last year but I seem to recall it as being just a few days to maybe a week (that would be at the very outside). At first my scores (all) dropped, 10's of points, each CB doing so as the new AMEX hit. Of course I thought "oh K-RAP what went wrong!?" and I couldn't find anything other than the new AMEX being the cause (same as you) then later, BANG AAoA went up (none did the same reporting day that I remember) and BOOM 40 to 60 points added to each CR! Fakos included. It was the sigh of relief heard around, well.... the room 
I'm guessing it may do the same thing again when the new AMEX Blue hits, but at least this time I'm somewhat prepared for it
Oh btw, welcome to, or welcome BACK to the 1989 AMEX Family 
Man I feel better!!!!!!!
Al I want is my 22 pts back but if I get more then GREAT.
I love AMX, still have my original Gold card from 1989 thoght its been upgraded to PR.
Thanks again and I will keep the forum updated on what happens to my issue here.
Something odd I have to add. Since I started looking at my CRs years ago, I noticed my old AMEX Green from 1989 would "blink" on and off of reports. When the Zync hit, it was "on" then I think "blinked" to off for good after a few months. So when a new AMEX reports with any others, open or closed, reporting, I think it affects the calculations for ALL AMEX's on the CR, at least during "the bounce" phase.
So 669, if you had other AMEX's reporting, esp if open, I think the new AMEX causes the others to follow it in "the bounce" (ok, call it the AMEX Bounce), meaning their age is pulled from score calculations even though showing and AAoA staying the same. AMEX is a unique product, even to scoring systems when it comes to the AAoA algorithm IMHO.
[EDIT]: I would surmise that would cause a temporary but serious back and forth "bucket dumping" in scoring, as it would appear (to a computer) the AAoA, new accounts (that aren't to be listed as new) and history, were all changing around at the same time (in ways they're not meant to be able to do).