F40: Oil level check while engine running?

We know, the manual says: run engine at idle for several minutes until oil temp greater than 70 Celsius and then check the level immediately after stopping the engine.
So what does 'immediately' mean? One second, or 30 seconds?
This is a wide difference because our oil is running back so quickly and the stick doesn't reach it anymore.
Does someone check the level while engine running? Some mechanics prefer that - somehow in contradiction to the manual.

Thanks for any advise,

cinque

 

Was also my meaning and this works well with my F355 and F550.
The difference is: If we want to see some oil on the F40 stick we need to be much faster than 30 seconds.
Now we check 5 seconds after stalling the engine.

9 liter needs to be in the system, so the manual.
See, after oil change and refilling almost 9 liter we like to get a proper feedback on the oil stick.
If you wait too long (30 seconds) after shutting down, you get a 'underfilled'.