Components are individual cost line items which include, among oth
er data, a quantity and a unit price that result in a cost. When more detailed information becomes available, the estimate evolves – new Components that describe the current Component in more detail can be added below it, thus forming an n-tiered structure.
The set of new Components remains inactive until the user decides that the full scope of the current Component is covered. At that point, the new Components are activated and the current Component evolves into an Assembly that reflects the sum of the included Components’ cost. The new cost is automatically compared to the previous cost ensuring that any change will be immediately tracked.