Though that depends on what the remaining 4% is. Curious about that. (E.g., for an aircraft the engine being local is more important than the seats being made locally.)

If I were to speculate, I'd say hitting 96% indicates that 100% is an important target to them. That would imply that the remaining 4% are pretty difficult to replicate "in-house" on a short timeframe (though obviously not impossible given the will and time to do so). All speculation though.