I've been told to replace our month-end Excel pack with Power BI, and I'm the one who gets blamed if the numbers change

Leadership mandates moving the month-end Excel reporting pack to Power BI. The pack contains linked workbooks, manual adjustments, and stakeholder-memorised numbers. Without a parallel-run plan and reconciliation process, any variance lands on the reporting owner.

This is a researched blocker from Microsoft 365 Report Builders. Below is the solution path — from understanding it to a paste-ready asset.