There is a python script that can do this effortlessly and precise: breakDashes.jsx
If you take five minutes to learn where to paste scripts into the right folder and then inside Illustrator go to file > scripts > BreakDashes
You might also need to signup to GitHub too in order to download the file.
It can be done via scripting, but why for? Just rename the folder Links1 to Links and reopen the document. Then, If you need, rename the folder Links back to Link1 and rename the folder Links2 to Links. And reopen your doc again. And so on.
The script does just the same thing:
Initial folders: Links, Links2, Links3, Links4
Run script 1: Links <-- former ...
You don't need a script to do this.
You could record an Action, and assign it to a function key, then increase the black by 10% using Edit > Edit Colors > Adjust Colour balance. Then record a similar second Action assigned to another function key, but this time to decrease the black by -10%.
Here are two such Actions I recorded. One named &...