Mariajobrador I’m not sure about the correct formula format to use in the relevant field for the change to take effect
Formula? You don't need any formula. As you can see in the placeholder, the field specifies the offset in seconds. If you want to advance the TC by 10 seconds, you must set the field to: 10. If you want to reduce the TC by 5 seconds, you must set the field to: -5.
Only numbers are accepted. Positive numbers to advance, negative numbers to reduce.
I hope is clear.
Best