WP Smush Pro all images are smushed/189 images need smushing

I've signed up for the 14 day trial, uninstalled WP Smush and installed WP Smush Pro. I ran Bulk Smush, and it ran through my images and attachments, then shows "All images are smushed and up to date. Awesome!". Then if I click Re-Check Images, it comes back and says "Joni, you have 189 images that need re-compressing!". After the Bulk Smush, it says that 359/546 attachments were smushed, then after I click Re-Check Images, it says 13/546 attachments are smushed, and 189 imaged need to be smushed. Perhaps I'm not understanding the nuance between "image" and "attachment". Is there something I need to do to effect re-compressing? Thank you.