There should be a special circle in hell for companies abusing velocity as a metric. Story points are made up points and looking at their velocity or acceleration will result in noise. Managing that noise may look useful, however, it is waste of time. It is as useful as going to the seaside and writing reports on underperforming waves.

What is useful, is to understand why certain task take longer than anticipated and learn lessons from that. Were there hidden requirements or was the task too ambitious and should it have been broken down in smaller tasks.