I've often puzzled myself over this weekly reach is actually calculated. I get that it is a rolling week of data, however I have often counted up the reach of the last 7 days and it's about 3x the amount that weekly reach is. E.g. it may say that my weekly reach is 5 million, yet I'd been getting 2.5-3 million per day. If you add up the values in the insights graphs it also doesn't add up to the weekly reach. Anyone have any ideas?