Fredoscale stretching is good for more complex windows. It makes components unique, including nested components which are stretched. Sometimes this doesn't fit with your component strategy. You have to decide when and how to use this powerful tool.
Windows and doors are definitely the most use I get from this tool. You've made one and you really don't want to rebuild for all the different sizes you need. The most work is going in and renaming the various components properly so you can use them by name in the future. I've never been able to be truly diligent in this regard.
I have seen the tool do some strange things with multiple nested component but usually it handles anything you throw at it.