Change effective on 19 April 2017
Application Metrics events are displayed as rollups of 1 minute to 2 hours of data, depending on the timeframe selected. To minimize the impact of Autoscaling event details on metrics chart visibility, we’ve removed the intermediate scaling steps and display only the steps when the autoscaling changed direction in event rollups. In the following example the number of dynos scaled down from a max of 3 to a minimum of 1, but the intermediate step of 2 dynos is not shown.
More information on Autoscaling is available here.