Transaction definitionGross sales, net sales, tax, shipping, discounts and refunds can be included differently.
Attribution modelAd and analytics platforms may assign purchase credit to different touchpoints.
Time & currencyTime zones, processing windows and currency conversion can shift period totals.
Privacy & consentBrowser restrictions, consent choices and modelling can limit observable events.
Returns & cancellationsRefund or cancellation timing may be represented differently from the original order.
Practical approach: document the intended source for each decision instead of forcing every platform to display the same number.