In Croatia we have few taxes to calculate. One of them is fixed tax for every sleep over per person.
example:
one person - one night: 1 x 1 eur
one person - five nights: 5 x 1 eur
two persons - five nights 2 x 5 x 1 eur
I saw that you don't have that option in system. However it can be done through "extras" where you can make it mandatory.
Question: What option in "charge type" is that ?