The "ExtractedByWinReducer" folder is the folder in which you could find all extracted files from an ISO. So, this is not the folder in which you could store your finished ISO.
The option to change your finished ISO storage folder already exists in WinReducer. This is not easy to find, because I want it like that : to avoid troubles for beginners.
So, let me explain how you could change the ISO storage folder (also described in the "HowTo.pdf" file in each zip package) :
1 - Launch WinReducer
2 - Go to "OPTIONS" icon
3 - Go to "Config" icon
4 - Then in "Folders Detection" part, put on "OFF" the ISO button
5 - Click on the "ISO" name and a new window will be opened
5 - Choose a new folder to assign permanently this new location.
Just take care at the fact that, the folder needs to always exists. So, if the folder is not find by WinReducer, it will be reported as a critical error when you launch WinReducer. If you experienced such error, just do again the procedure I described and change to a new folder.
That's all to know ...