Not so, at least on the wife's Premier
1. Press the Lock button on the FOB
2. Immediately press the "turn over arrow" for at least 4 seconds or until the turn signal lamps flash.
Parking lamps should turn on and stay on as long as the engine is running. The vehicle's doors will be locked.
The engine will shut off after 15 minutes unless a time extension is done or the engine is turned on.
For a 15-minute extension, after 30 seconds repeat steps 1 and 2 while the engine is still running. This can be done only once.
When the remote start is extended, the second 15 minutes will be added to the first for a total of 30 minutes.
Now I did not use the FOB at all, just doing what I said early, so will have to try this method. I have no Key, just a push button.