FBA stock is Amazon’s to count, not ours
We always send your figure out. What comes back depends on who ships the item.
Every stock change we know about goes out to Amazon, so a Squarespace sale lowers what Amazon shows. The return trip is where the rule sits. Where you pack and post an item yourself, Amazon’s own adjustments come back to us and carry on to Squarespace. Where Amazon warehouses and ships it, we do not touch that figure. Which of your items are meant to agree depends entirely on that split.
The reason is that Amazon knows its own shelves. What happens inside those warehouses, from receipts to damages to returns, never comes past us, so writing our number over Amazon’s would be a guess dressed up as a sync. Leaving that count where it is means the items it covers are not supposed to match your Squarespace figure. A book number that quietly disagrees with a warehouse is worse than none.