What is Change coverage in the Review of a campaign?
When you reach the final step of your campaign and have more than one active channel, you can see the option Change coverage for estimated costs.
It helps you visualize the estimated costs for a selected country. You can see that in the example below the estimated delivery is 20% for Viber and 80% for SMS. This means that even though all the messages will be sent first via Viber, there is an assumption that 20% of recipients will actually receive the message and open it. The rest will be sent via the SMS channel.
However, this is only default settings. The real data can be completely different. For example, all customers can have Viber and all accept the message before the message expiration. You can toggle with the Change cover settings and see, how much would the campaign cost, if the numbers were different, as in the example below.