In terms of project cost management, iterative budgeting is seen as solving many of the problems presented by relying on

[answerhappygod]

In terms of project cost management, iterative budgeting is seen
as solving many of the problems presented by relying on either of
the two major approaches to budget information-gathering (top-down
or bottom-up). Explain how iterative budgeting works and how the
alignment of estimates is achieved and give one disadvantage of the
method.