Milestones are mandatory both according to project requirements and contractual requirements.

Control points for senior management can be located at selected management points above the level of the work package.
Control points for control accounts can be used as a basis for planning when the relevant work packages have not yet been planned The planning portfolio is used to plan known work elements for which specific planned activities already exist. The planning portfolio is a component of the work breakdown structure below the control account in the work breakdown structure but above the work package.55. The following statements about milestones are all correct The planning milestone list lists all milestones The milestone list is used in the schedule model