It would be a awesome to be able to create a new custom metric that allows you to go back holistically.
I found out the hard way that if you find the data within logs and create a new metric. The new metric can't poll the same data in the logs.
I have a date set for 30 days and find everything in the logs using a query. I then create a new metric. The metric only provide information when it was created and going forward.
Hope someone can fix that in a future release, or