SmushIt Pro appears to not be smashing/optimizing all images

According to my Hummingbird performance report, I need to optimize my images. However, I've already configured and run Smush Pro and optimized all images in my media library. My "Improve Score" benchmarks on my report lists a pretty lengthy number of images that should be included in the Smush Pro scan. When I check the media library, it shows those images HAVE been smushed. Any help as to why they are still showing up as needing optimization when they've already been smushed? I have attached a few screenshots for your reference. Let me know if you need any additional information.