yes new implemented features can be annoying especially if you used to the old one and you loved how it worked.
The solution is to select all the plants you want at a certain scale after you copied/instanced them in the scene graph. Than you can move the slider back to the plant's % you started with
Not perfect but it works at least in one go.
Carsten
www.asmtechbase.com
https://www.youtube.com/asmtechbase
AC 3 to 26 -Windows 7 - 24GB - 8core 4.4Ghz