Do Issue links regardless of type have any account on reporting truth on completion percentage?

[Becke]

I need to report completion percentages and it looks to only be an estimate with how teams have been creating issues. 

Ex. 

Parent is created 

1 - Epic is under Child Issue 

3 - Epics are under Issue Links with  "relates to"

For the 3 Epics under the Issue Links does this go towards the work required to close out