Facebook Ads Manager vs Google Analytics Cost Data
Facebook autocorrects cost, impression, and click metrics over 24 – 48 hours.
These changes are usually minimal but can be why you would see some small differences when looking at data in Google Analytics with a date range through yesterday.
Our system imports cost data daily with a lookback window of 7 days to ensure that cost, impression, and click data is up to date and reflects any adjustments Facebook has made.