got some similar problems at EDDW - spot has no parking codes, handling is done by SWA, China Airlines, ... - Catering bei SATS (Australia) - if parking at another Sport with parking codes handling is done according to parking codes, catering also wrong.
It looks as if (for EDDW) the airport code is ignored.
I tried to assign AHC to EDDW, no joy
(latest GSX build - clean Install, FSX-SE)