We have clients doing social commerce and set the cost per message as the KPI.
Our current workaround is to convert it into the number of messages. However, this is not ideal as the budget changes from time to time.
For every Facebook custom conversion you have in your account, the system automatically creates a "Cost per" metric for you. Is your current message setup as a conversion?
Not custom conversion but the New Messaging Conversation for Message campaign. The metric is there already. Just missing the cost.
We have just added the new metric "Cost per messaging conversation started" to the list. Please give that a try and let me know if you need any others.
While daily performance and target look fine, MTD's calculation and display number seem incorrect.