RomRaider

Might be a silly question .. is there any logic to the CAL or ECU ID's that Subaru use ?

Reason for asking I've got two stock ROM's with CAL D2PH410Q & D2UK001Q with the same vehilce desc in RomRaider. Both for 2007 3.0R Legacy AT, tables are mostly identical aside ignition timing & DBW.

This got me wondering if the ECU or CAL ID holds any clues for the target market/fuel/emissions etc...