Hi,
I have been trying to solve the scaling problem in recent days. I used multiple Actors to form a house, and then I want to scale it as a whole. By default, they will have some strange changes. The various parts of the house will be scattered and cannot maintain their relative relationship. I found some methods, such as using blueprints or attaching them to another object. Now I found “Use Percentage Based Scaling”. When I enable this option, scaling multiple objects will meet my expectations. The description of the option is "If enable, use the old-style multiplicative/percentage scaling method instead of the “new additive/fraction method”, other than that, I couldn’t find any relevant information. My question is what situation is suitable for this new additive/fraction method, and why is it the default option?
The typical editor behaviour is to scale the relationship between objects as well as the objects. With the old percentage method, the relationship remains, but is scaled.
If I put a sphere on a cube, but off centre, the old behaviour is:
new is
It’s also magnifying the offset. Apparently, that’s what most people want, more of the time… 
Thanks, this solved my confusion:)