The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
This app is simple and straight to the point. You will not find a better price. I really hope they improve their analytics and offer more features like dynamic offers.
Happy to say that analytics have been completely revamped and there are now in-depth analytics at both the store and promotion level. You can see a number of metrics across different time-frames. Hope this helps!