This article is a quick rundown on how the booking system constructs the room prices in the booking form.
When the booking system calculates prices first it finds the 'base' cost of each room, per night or per day. This is the figure pulled from the tariff rate.
Then it will look at all of the rooms & tariffs selected. Say for example two rooms have been selected, one at Tariff 1 (€50pn) and the other using Tariff 2 (€100pn). The base cost of these rooms would be €75pn. Now it looks to see if any Guest types exist for the booking. If there are no published Guest types for the property then by default the guest type selection drop down isn't offered or considered in the calculation. If they do exist and if the property is configured to charge on a per person per night basis then further calculations are performed based on the value of each guest type. If it is not, then although the guest numbers are included in the booking they are not considered in any way in regards to pricing.
Within the booking engine the Guest Types are part of a larger group called Variances. Variances are elements in the booking who's cost may be calculated as a variance off the base cost of each room. Say for example you have two adults and two children in the booking. Adults are charged at the base cost of the rooms, whereas the children have a 50% discount (see Guest Type configuration for more information). The cost of the adults will be whatever the room costs (€75), whereas the children will be half that each, or €75 for them both. The Total would be the cumulative value of all four individuals, and the Grand Total: would be the total * number of days staying plus Tax, Single Person Supplement (if applicable) plus any Extras. The booking system does this all seamlessly, depending on your property settings, meaning beyond creating rooms and tariffs, configuring your property to charge per person per night and creating the relevant Guest Types, you don't need to edit anything else to enable the calculations to take place.
Discounts Wiseprice (or) Lastminute, and Discount Coupons are designed to adjust base room prices based before other totals are calculated. See their individual pages for more information on the specific items. It is also possible for you to configure a guest to have a specific discount every time they book (guest specific discount). When adding or editing a guest in the Guest types page, you can configure them to always get a percentage discount every time they book. This requires the guest to be logged in when making the booking.