The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
It has issues. After I installed the app and after I pressed the add to cart button, my products weren't added to the cart instantly, I needed to reload the page for it to show up in the cart.
It appears this has been an issue unrelated to this app. We confirmed that, after you uninstalled the app, the issue was still there.