Build pivot tables for summaries

I need a clean set of monthly summaries from the raw transactions. Build pivot tables that show total amount by account and by month, with a separate pivot for department vs. expense category. Put the two pivot sheets after the raw data sheet, name them Month by Account and Dept by Category, and refresh them so numbers match the latest rows. Before you finish, scan the raw data for blank dates or negative amounts and tell me any exceptions you fixed.

Before I send these summaries to finance, make the pivots easier to approve: put the overall total and savings highlighted at the top of Month by Account; add slicers for Month and Department; move the most volatile accounts to the top; and create a one-row explanation of any unexpected large swings under the pivot. Flag any source rows that feed the large swings so reviewers can inspect them quickly.

I refreshed the pivot and the total for April jumped by 18 percent compared with the prior refresh. The raw sheet is Jan–Jun transactions, and I only have myself, Priya in finance, and the department head as stakeholders. I’m afraid it’s a data or mapping error but I can’t tell if someone overwrote a price column or if duplicate rows were imported. What is the most likely cause and the step-by-step checks I should run now to find and fix it without alarming the others?

Every month I rebuild pivots and twice I’ve had to explain a 5–15% mismatch versus the official monthly report. I spend hours hunting formulas and chasing people for cleaned exports. Where am I wasting time and what habit should I change so my pivots match the official numbers first time? Suggest one checklist item to add to my handoff and one structural change to the team’s export process.