You also could have installed the extensions, not stretched the springs nor used a file, test-fired, and then picked up the file if necessary and test-fired.
From Hennings: "For 45 ACP you will use the factory follower and spring. To ensure the factory follower does not get stuck, take a file and round the front top of the follower so that is more rounded. There are no aftermarket follower/spring options for 45 ACP. Using the factory follower you will get 12 + 1 capacity !"
Nowhere is spring-stretching recommended.