They’re using “traditional search” to mean the shopping specific search widget or page, which is a separate feature from traditional search. It aggregates retailer listings and sorts them by price. The AI mode is based on normal top search results, which are oriented toward information about the product like the manufacturer’s page, which is usually going to be full MSRP. So technically correct that the AI mode is no…
It's not a trick. What you receive as shipping or taxes on google shopping are not the final ones, google doesn't have your full address, neither doesn't have info from the merchant for all taxes (depends on the country) and shipping applied to the product to all possible locations.
Google shopping result might show an accurate shipping fee, but at checkout you will notice a $50 fee that exactly makes up the difference between the retail price and their Google Shopping indexed price.