Originally Posted by
cygnus
In my experience, once the control of the flight has been turned over to KLM, DL does not see the correct seat availability. I believe that the reason for this is that DL and KL use different software for this (the GDS, or Global Distribution System). DL uses its inhouse system Deltamatic, while KLM uses Amadeus (I think). The hand over means that the status of the flight including the seat assignments gets loaded into Amadeus. All changes done after that are not mapped back into Deltamatic, which is why you cannot change your seats on delta.com after the 24h hour mark and why DL agents cannot see the current seat map.
What you're describing is actually ACI (Automated check in, or I've also heard it called ACS at some carriers (automated checkin system)).
GDS is for booking and inventory management. Day of departure flight activities (like boarding, upgrading, closing out a flight) are handled via ACI. These two systems are connected, but not the same thing. Por ejemplo: KL doesn't need DL's GDS access to sell or rebook their flight...they already have their own. However, they do need DL's flight access to ACI to work the DL flight. They use that in their own SW (and so do most other carriers), but only if DL provides the access for them to work the flight. Generally airlines share the minimum in ACI with partner carriers. Just enough info for them to work the flight. Could be a reason for the discrepancy.
I've had mixed luck using GUCs from AMS too. Once they begrudgingly upgraded me at the gate, and they forgot (?) to attack my GUC so I was able to use it again...other times they wouldn't even try to upgrade me and seats went out empty in D1.