When a guest in Booking.com tape number of children, the web open a new window with the "age old" for each children. So the book add number of adult and children with the rate for each.
BUT WITH BOOKINGBUTTON
The page don't take the children only the adult. And for the children don't open a new window for the Age old.
So when you select for a room for 4 persons, 2 adults and 10 children. BookingButton accept the reservation and charge 2 adults ONLY.
When Booking.com will charge you 3 rooms for 4 persons each
PLEASE FIX IT ASAP