Extra cost table manipulation

[Ben]

Excellent, application. I am using it for a managed apartment complex.
The owners have 16 different rates and have different prices for 1 to 7 night stays rather than just 1 rate multiplied by the number of nights. To confuse matters, the increase per each night is not consistent with other rates, so I have to create a base nightly rate and add a negative extra cost for each. This is about an extra 80 costs I will have to create to get it to work. My question is does anyone know of a better or easier way as maintenance will be a nightmare.
I have considered setting it up like this and manipulate the database to maintain it direct which should cut down the time.
Although married to an Italian I think she only knows the bad words and isnt much help in deciphering the table and column names. Any ideas anyone? What table are the extra costs located in?

Any help appreciated. It truly is a great application.
Ben

[marco]

Hello Ben,
the data about extra costs characteristics are in the table ntariffe2006. The price (value) of the cost is in the column valore_ca. Tell me if you need explanations about other columns.

Marco