The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
I would also like to comment about the poor print quality. If having your items properly sized is important to you then I would recommend finding another service to use. The support team told me personally that their mockup generator isn't 100% accurate but the designs came out half the size of what the mockup generator shows - and that's more than just not "100% accurate" in my opinion. I will compliment their fulfillment speed though, everything I placed through them was fulfilled and shipped in a very timely manner. I just wish everything was the size I was led to believe they would be.