Here's some more food for thought — Despite of what one might expect, the lap times DO NOT get better the longer the training session is! In fact, they get
worse!
The best lap times are normally achieved within the first 10 laps of a training session.
Here's a record of some 400 lap training sessions. As you can see, the best lap times are done in right at the start, and then they go up.
The only thing that additional laps achieve is to make the lap times more consistent (there are fewer wiggles in the graph), but they're way slower than those at the beginning:
One may suspect that the learned "wisdom" isn't applied until a new session is started (or the game itself restarted),
but even that is not the case.
Here's two charts where the game was restarted after 100 laps and 23 laps each.
Same result. Fastest time at the beginning, and then it slows down:
I really don't know what to make of this...
Perhaps longer sessions make sense on tracks that have a really crappy AIW? (I did the tests on 60's Spa, Brianza & Östereichring.)
But for any decently prepared track it seems like a waste of time to do more than one 23lap session.