Does the DA need existing and proposed site levels?

Yes, for developments where levels affect the planning assessment, the plans need enough level information to show the existing site and how the proposed development will sit on it.

This is particularly important where levels affect matters such as building height, finished floor levels, excavation or filling, retaining works, driveway gradients or the relationship of the building to the surrounding ground.

For example, on a sloping block, a section through the proposed dwelling should show the relevant ground level and proposed floor levels so the building's height and relationship to the land can be properly understood. ACT Planning describes section plans as including ground, floor and ceiling levels.

The exact amount of level information required will depend on the proposal and the matters that need to be assessed; it is not necessarily the same for every DA. ACT Planning requires the DA documentation to address the relevant Territory Plan provisions and include the supporting plans necessary for assessment

Reference: ACT Planning – Development Application Naming Conventions -https://www.planning.act.gov.au/applications-and-assessments/development-applications/before-you-apply/naming-conventions