Consolidate multiple sheets

Combine the quarterly sheets North_Q1, North_Q2, North_Q3 and North_Q4 into a single consolidated sheet named North_Year. Keep source sheets unchanged. Ensure column formats match and remove duplicate invoice lines based on vendor+invoice number+amount. Produce the consolidated totals by cost center at the bottom and validate that the year total equals the sum of the four quarters before I hand it to the regional controller. Ladder":"L1"

Before I send the consolidated workbook to group reporting, make it easy for them to validate totals and find exceptions: produce a pivot-style summary by cost center and quarter, put a clear discrepancy flag where a vendor’s quarterly subtotal differs by more than 0.5% across consecutive quarters, and surface any duplicate invoice numbers coming from different quarter files. Also include a one-line note describing how duplicates were detected. Ladder":"L2"

I just merged four quarter sheets and the year total on North_Year is different from the sum of the quarter totals. The controller will ask for the reason. I’m not sure whether I accidentally duplicated rows, omitted a column, or left hidden rows in a source sheet. What diagnostics should I run in order to quickly locate the discrepancy and the best next action to fix it? Ladder":"L5"

Every quarter end we spend days reconciling consolidated sheets: manual copy-paste, hidden rows, formatting mismatches and duplicate invoices slow us down. Where are we losing a day or two each quarter, and what consistent habit or small template change would cut that friction so consolidation is reliable with one pass? Ladder":"L6"