Wrong on several counts. You can look up AV stars on fuzokuav and see what shops they are working at and their rates. They generally start around 3. for 50 min.
As a general rule, no first tier (or second) AV stars work as deriheru girls. A few do, but super UTR, and generally only in places like HK or Dubai at absurdly high rates (5 digits+). Most of these girls that have contracts that risk their livelihood if they are escorting, much less for tourists.
There is a rare occasion that a famous girl like Rin Kajika will pop in or out of a high-end shop for a week or so. Usually they book up way in advance and their rates may be higher than typical by 5k yen ($50) or so, but not much more.
FS is "not allowed" in Japanese sex work because for legal reasons advertisements cannot be explicit. It does not mean that doesn't happen or isn't implied. Almost NO girls, much less true AV stars, offer greek.