Cost Rollup Report | purpose | time gap to trigger

Summary:

When we Rollup the Cost for the previous site, below ESS Jobs will trigger in sequence.
Roll up Costs > Rebuild Rolled-up Costs > Cost Rollup Report

1. There is 3 mins gap between the completion of "Rebuild Rolled-up Costs" to the start of " Cost Rollup Report" . Any reasons for that?
2. " Cost Rollup Report" - looks like gets triggered if the submitter has the privilege. If submitter does not have privilege, it will not trigger.
3. What is the significance of " Cost Rollup Report". Is it just BIP report or does process anything ? Is there anyway we can stop this from triggering (other than removing the privilege) ?