Published averages mix newsletters and personal emails, different industries and different ways of counting, often including machine opens. For one-to-one business emails, a reply tells you far more than any open rate.
In HawkOpen every open and click has a category, so you can see how many events came from Apple Mail, a provider’s proxy or a scanner, and how many showed no sign of a machine (observed, which does not mean a person). Use the same way of counting when you compare two periods or two versions of a message.