The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
I've contacted support twice with no response. I want to love this app, the label design is perfect for our needs, but they print out with no barcode - just an error message about the barcode data being invalid. I had to delete the app after the trial because of the lack of support and inability to fix the problem with the barcodes.