Export report data to CSV

I need the report data exported to CSV so finance can reconcile commissions by Monday. Export the closed-won deals report named Q2 Closed Deals, include Opportunity Name, Account Name, Close Date, Amount, Sales Rep, and Commission Rate columns, and filter to closes between April 1 and June 30. Verify the file opens in Excel without formatting errors, then upload the CSV to the shared drive and tell me the path.

Before I export Q2 Closed Deals for finance, make the CSV easy to validate: move Amount and Commission Rate to the left, add a validation column that flags blank Commission Rate or non-numeric Amount, and include a header row that spells out the date range. Also note any rows with duplicate Opportunity IDs so I can check for split-commission errors.

I exported Q2 Closed Deals and the CSV truncated at 65,000 rows; finance says they need all records for commission reconciliation. I don't know whether the system exported a sample or my filter cut data. The finance deadline is Monday and they will audit totals. What's the most likely cause and the fastest reliable fix I can do now?

Every quarter I spend hours re-exporting reports because totals or row counts differ from finance's numbers. I waste time reconciling versions and redoing filters. What habit or check should I adopt so exports are complete and consistent first time and I stop firefighting before each commission run?