Seats are priced per person, and the whole boat is priced per band. Put them side by side at the same head count and the crossing point shows itself.
On Akassa Cruise with 10 guests, the whole boat comes to IDR 7,800,000 (≈ USD 479) each, below the IDR 9,500,000 (≈ USD 583) of its lowest Friday seat. On Derya with 10 guests it is IDR 6,900,000 (≈ USD 423) each, and Rinca and Kanawa seats cost IDR 6,500,000 (≈ USD 399). On Giona with 10 guests it is IDR 5,200,000 (≈ USD 319) each. A Triton seat costs IDR 5,000,000 (≈ USD 307), and a Poseidon seat IDR 6,200,000 (≈ USD 380).
For two guests the picture is the opposite. Two Thetis seats are far under the IDR 45,000,000 (≈ USD 2,761) that the whole of Giona costs for 2.
A small party in one cabin takes a seat. A party that fills the deck takes the boat, and the charter page prices it by route and guest band.