Tooltip current version: 'The "Save As ..." dialog uses the current working directory for saving (if the file was previously saved). If not previously saved, the most recent "Save As ..." directory is used.'
Still confusing?
Yes. What does it mean "if not previously saved" and "the most recent "Save as..." directory"? The previous version was more clear. Moreover, specifying the behavior when the user didn't use 'Save as...' yet is unnecessary. It's logical that it will open in the current working directory, and this information is not relevant to the choice of enabling or disabling this option.
Better version of the tooltip:
"When this option is on, the "Save as..." dialog will always open in the directory where the currently open document is. When it's off, it will open in the directory where you last saved a file using that dialog."
Regards, Krzysztof