It is possible to change shrinkage by scale in Creo's base package but it does not leave a tree item for the change. This is potentially quite dangerous to make a change to shrink as there is no record in the feature tree showing this change taking place. You can end up with an unintended size without having a clue in why the model got to this size.
The tree item for shrink was removed from the software; this function was possible in Wildfire. You can still see the shrink feature when you retrieve a Wildfire created part into Creo. I've attached how this shows up in Creo's feature tree. I would like this functionality returned to Creo as this potentially could lead to very costly mistakes.