Reports for future planning based on Story points ?

I have some doubts on below - 

So, we have a structure for our PBIs - Feature->Epic->Stories 

Currently my PO is maintaining a report where all story points linked to all stories are realized into a chart/graph.

Now, at the end we have a measurement of the story points used in an Epic. Example - An Epic 'Tango'  = 100 story points.

This information then further used to plan the future Epics , like new Epic 'Charlie' should be approximately 80-120 SPs considering what the consumed in Epic 'Tango'.