The seasonal calendar price-chart rentals are the final prices payable if the guest party leader rents the entire villa with the full complement of adult beds occupied.
For the individual villa rental price charts, see the villa page under main-menu tab "All Skiathos Villas".
However ... if asked, owners may offer discounts for smaller groups, or family parties with school-age children - particularly outside high season.
To find out and negotiate, contact the villa owner via the villa page "Enquiry" tab (or tel. no. /website if given).
There is no additional booking fee payable to the owner or to the "Skiathos Greek Villas" website, and no commission is paid by the owner to the website (which would pre-inflate the chart rental). But if you see the same villa on any of the "usual suspect" booking websites and book via them - such as HomeAway.com [also via owners-direct.co.uk], Air-BnB, Bookings.com, etc. ... then these price protections do not apply, and in most cases you will pay more.
The only major site left which does not in some way inflate the price is "www.simplyowners.net" * (click to compare Orchard Villa with others ... opens a new browser tab, click tab: "Skiathos villa owners direct rentals" to return here)
* we and other "Skiathos Greek Villas" owners use this site.