When a call to a Setter function returns, the setting may not yet be activated within the black box. Your code can call a Settings Getter function, and check the returned FF_SettingStatus_t parameter to determine the status of the setting at any time.
Also know that when calling Setter functions, sometimes the API or the black box will coerce the setting to a different value than what was specified in the argument list. When this happens, the displayed setting in the user interface should be adjusted to agree with the setting value provided by the API Settings Getter function. See Setters.