Trying very hard to compare apples to apples. Chill Out quote says

"The prices below show both the “one way” cost and the total round-trip price if required. A round trip booking attracts a 10% discount on the return journey (excluding international processing fees).
International processing fees cover: Clearances in & out of the BVI, St. Thomas dockage, BVI port fees, cruising permits, environmental levi, USVI port fees & USVI port passenger tax. They do not cover the covid arrival tests required for all passengers at the Port of Entry"