The Property Growth / Depreciation Rate is the initial, default rate at which property, at least once purchased, will increase or decrease in value. A negative value could be entered in cases where a depreciation rate is deemed appropriate.
The setting in Plan Settings, will apply to the client case that you are presently viewing. This assumption can also be edited on a per scenario basis within the client case.
For a future property purchase, the Inflation Rate is used to compute the future value of a property when purchased.
This default setting can be overridden for any individual property or asset in the plan by adjusting the Growth Rate % on the Basics screen of the Property.