If you want to apply a lower price from the first night on you can do this using two rates.
Example1: 1 night costs 120 but if a guest books 3 or more nights each nights costs 100.
Rate 1:
"Minimum Stay"=3
Example 2: One night costs 220 but if a guest books 5-6 nights each night costs 210. From seven night each night costs 205, from 8 nights each night costs 200.
Rate 1:
"Room Price"= 220
"Minimum Stay"=1
Discounts tab:
5 Nights: "Per Night" = 10 "Once Off" = 40
7 Nights: "Per Night" = 5 "Once Off" = 30
8 Nights: "Per Night" = 5 "Once Off" = 35