It would be very helpful to be able to compare the current sound with the saved Preset. If I tweak a saved preset and I want to know how it has changed from the saved values, there’s not an easy way to compare. Do I want to save over this preset? Is it better? I don’t know! 
When you have pressed Save, you can preview any preset. At first you hear the edited version. To audition the stored version, turn the Preset knob to the next/previous preset and back again to the preset number you were working on - now you hear the stored preset.
Edit: There’s also the Snapshot feature (User manual: 4.5. Sound Edit operations), which could be used (just load the old sound, a snapshot of the edit is then stored and can be recalled again). BTW, a shortcut to the snapshot menu is Sound Edit + Save.
Thank you friend. This is helpful!