Hi Guy - it sounds like you've got it all figured out now!

So yes, the XYZ input area is for typing coordinates in right when MoI is asking you for a point coordinate, like for example during the line command or during some kinds of actions like transform commands too.

If you type coordinates in that particular area after the command is totally finished it won't do anything then, numeric object resizing is separate from point input - object sizing is handled by that separate place in the properties panel which shows the different properties of the selected objects.

- Michael