I will be using a Shield for the test.
This ^With consistent properly manufactured ammo the greatest variability in accuracy is you.
Don't obsess on the ammo. Obsess on the training. Focus on trigger control and consistent hold control. Remember, that of the two (sight alignment and sight picture) sight alignment is the more important and will contribute more to accurate shot placement.
In most evaluations they use time to artificially create tension. You should have plenty of time to get off the required shots accurately so it's often best to ignore time limits and just pace things fast enough to leave a little extra time if you need it to clear a jam.
Learn to press check to ensure your chamber is loaded before an exercise. Learn to recover if you get a jam or mis-feed.
Make sure that your firearm functions reliably with the ammo you choose. This problem alone can cause you to score low enough to not pass...