Update Advanced-Idle.md

Updated to reflect when the Coasting Idle Table is used and how it is determined. This could probably go in a separate "phases" reference later.

https://github.com/FOME-Tech/fome-fw/blob/fabfd6a41311d637eb9c34ee525e31d630ca4610/firmware/controllers/actuators/idle_thread.cpp#L55-L62

docs/06-Basic-Features/Idle-Control/Advanced-Idle.md

@@ -6,4 +6,4 @@ Setting this value to __true__ enables the use of the Idle Ignition Table and Id
 ## Coasting Idle tables
 Setting this value to __true__ will enable the _Coasting IAC Position_ table. This will manually over-ride the Idle Air Control valve position during the coasting phase. This can be used to help reduce engine braking and may be useful if the engine has difficulty returning to idle.
 
-The coasting phase is determined by checking if the current RPM is greater than the maximum idle RPM (_Idle Target RPM_ + _RPM Upper limit_) and the engine is no longer in the cranking taper period.
+The coasting phase is determined by first checking if the TPS (or throttle pedal position if using ETB) is less than the _TPS Threshold_. If so, FOME next checks if the current RPM is greater than the maximum idle RPM (`Idle Target RPM + RPM Upper limit`) and the engine is no longer in the _cranking IAC taper duration_. If all of these conditions are true, the engine phase is coasting and the _Coasting Idle Table_ is used.