Richard,
To attempt the AI to Online Approach, you would probably have to have it defined to do that at a certain location. This would require a ton of engineering and personalization per airport I think. For example, most approach controls arent a circle so you couldnt use a base mileage from the airport. You would need to define a fix for every instance. But what if your flight plan doesn't have a switchover fix? What if you're an overflight with the switchover fix in your route? What if the airport in question uses a different approach control first for example, KMDW landers from the east go through South Bend Approach then go to Chicago Approach.