That is correct. The ‘get-forecast-daily-volumes’ and ‘get-forecast-monthly-volumes’ endpoints implement the logic found in this forum post as a convenience to transform the Forecast Outputs to Forecast Volumes. This can be a large amount of data though, so your individual use case will determine which option works better for you.
It should be noted that the ‘get-forecast-daily-volumes’ currently exports only the first five years of the Forecast Volumes. We have items on our backlog to add a date filter to this endpoint to allow pulling different/larger sections of the volumes. The ‘get-forecast-monthly-volumes’ endpoint does not have this restriction.