Shooting rimfire bullseye leagues almost exclusively, I found that slow fire was not my friend and I tended to shoot it just like I do timed fire.
This league I switched to an M9 NM pistol to start preparing for Camp Perry.
Everything was reversed. I take close to the whole 10 minutes to shoot slow fire and timed fire is no longer my friend. I now finish timed fire just as the whistle blows to stop.
I've also learned that if all you routinely shoot is rimfire, then centerfire will come as a rude awakening.
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.