You are probably misunderstanding FS1-3. These are the "alternative mode" switches – for example if you are in PLAY mode, these would be the otherwise inaccessible switches in PRESET mode.
You will also confuse yourself if you use one switch for multiple functions as you describe. To set it up as you describe in your first post, you could:
1) Set Tip to bypass
2) Set Ring to PRE+
3) Set Tip&Ring to PRE-
4) Make sure that the AUX switch is not controlling anything else.
These are covered in p.36-38 of the UM.
