I’m guessing the homeowners are big fans of Dr. Seuss or their landscaper tried really hard to get the shrub tiers straight, but it didn’t end well. This reminds me of my Momma trying to cut my bangs straight and I would hear “oops” and she would go back to the side of my head and try again, and again, only to stop when my bangs were only 2 inches long. It did grow back. If this is your landscaper, stop them. There are correct ways to get an exact cut.
Take string and a ruler and measure the string for each level’s height of the topiary. Tie the string to the top and hang down to the ground. Take your pruners and clip very lightly where the string (don’t clip the string) is marked. Then take your level and balanced in into the shrub and cut the foliage along the balanced level. Eyeballing isn’t a good idea.
You can also take a ruler and just measure between the tiered foliage to get exactly the height you would like.
Clip very lightly. This is not a job that needs a pole saw trimmer, but small hand pruners. And it should take you more than 3 minutes to prune 3 shrubs.
If you like the Dr. Seuss theme, go for it. But think about adding garden art to your beds, or large colorful orb or whimsy, so it looks like it’s a deliberate magical garden theme. If your landscaper is having “oops” moments, it’s time to find a new landscaper.