Time based scale

Hi,

I have set a condition type with an Scale Based Type: N Year. Then I have created the condition records as the following:

from 0 to 2 years it charges a value of 10

from 2 to 4 years it charges a value of 15

more than 4 years it charges a value of 20.

But when I create an FS Quotation for that pricing procedure it is always charging 10.

It doesn´t seem to be afected when I change the duration (I do this by the Valid From and Valid To Dates from the header and the item).

My questions:

Should I use another fields to set the duration?

Am I missing any customizing for a time based scale?

Please give your suggestions