[WP Smush Pro] WP Checkup says I need to optimize images - but smush pro installed

I have wp smush pro installed and it says it has smushed all my images, i also have the highest smush setting on.
However I ran your wp-checkup tool and it returned a long list of images which it says need to be optimized, when I look at the image stats it says they have been smushed.
Any thoughts?