Look at Results on the Dashboard. It puts your orders since you turned the bar on beside the orders from as many days before it, up to 30 days each: how many, the average order, and how many reached your free shipping threshold. They come from WooCommerce's own order records, not from tracking shoppers. Other things change between two periods too, such as the season or a sale, so read them with that in mind.
Still stuck? Ask the developers who wrote it. We aim to reply within one business day.
