We have different metrics between high season and low season, so we have to implement different pricing models.
In summer, we are virtually guaranteed to be booked at the highest rate. So, we price it "flat rate" for the entire villa, max 8 pax. Bookings normally are 6-8 pax. If we priced per person, the villa would be booked continuously in the summer for 2 persons at 25% of the flat rate, because it's cheaper. They might bring 8, but they'll book for 2. But it would be such a bargain for 2, that it would be booked for the whole high season for 2 pax, and we could kiss the higher rate goodbye.
In the off season, the main market is 2-5 pax. So, we price it per person per night, starting at 2 pax, and an additional rate for each additional person. If we priced it flat rate for 8, it would simply be too expensive for 2 or 4 or 6. Conversely, if we priced it "flat rate" for say, 4, it would be continuously booked for 6 or 8, because it would be so cheap, it's irresistible.
So, for us, this is why the per person rate is important.