Save to original source when batch processing files

The "same as source" box is grayed as I attempt to batch process files in Elements 11. I am attempting to save the processed files back to the original folder in PhotoMechanic and then I save the files to a folder on my desktop by using the Cmd S shortcut in P/M. I am able to resize the files with more accuracy by saving with this method rather than saving the processed files from the "Process Multiple Files" dialogue box. I then need to wire each of the files by FTP at the size of approx. 1.5mb each. I use an Apple MacBook PRO laptop