For vtkLODProp3D switching,is possible to get the previous LOD ID?

Hello,there four methods to get LOD ID

GetLastRenderedLODID
GetSelectedPickLODID
GetSelectedLODID
GetPickLODID

But their api docs are quite confusing for me,so I add an observer to render windows to listen ModifiedEvent,which will print all four LOD IDs when switching,and get output like this:

...
GetLastRenderedLODID: 1000
GetSelectedPickLODID: 1000
GetSelectedLODID: 1000
GetPickLODID: 1000

GetLastRenderedLODID: 1001
GetSelectedPickLODID: 1000
GetSelectedLODID: 1000
GetPickLODID: 1001

GetLastRenderedLODID: 1000
GetSelectedPickLODID: 1000
GetSelectedLODID: 1000
GetPickLODID: 1000

GetLastRenderedLODID: 1002
GetSelectedPickLODID: 1000
GetSelectedLODID: 1000
GetPickLODID: 1002
...

Based on these outputs,can I assume that:

GetLastRenderedLODID/GetPickLODID   will return  the current LOD ID
GetSelectedPickLODID/GetSelectedLODID  will return the previous LOD ID

If yes,what is the difference inside pairs?

GetLastRenderedLODID vs GetPickLODID
GetSelectedPickLODID vs GetSelectedLODID