When two financial views should agree and do not, the fastest path is usually to make the problem smaller.
Confirm the Comparison
Same company. Same period. Same account range. Same posting status. Same date logic. Same filters.
Find the First Place the Difference Appears
Isolate the account, period, source journal, module, batch, or transaction population responsible.
Trace the Source
Once the difference is small enough, follow it back to the transaction or process that created it.
Fix the Cause, Not the Spreadsheet
A reconciliation worksheet can document the answer. It should not become the permanent substitute for understanding the system.