If you generate a Sales By SKU Report but the SKU values in ShipHero do not match the number sold in your connected eCommerce store, it is because the report has not been refreshed and is showing a past snapshot.
Refreshing the Sales By SKU Report in ShipHero
The report data is automatically refreshed daily. To manually refresh the SKU values, go to Reports > Sales By SKU and click on the refresh option shown in the screenshot below: