In the character editor, you can't replace the Additional Magical Secrets with a spell of higher level once you are able to cast them. Is this supposed to be how it works? I thought you can replace these spells at later levels with another spell from the bard spell list, but is that only the normal magical secrets? In the character editor it does work for the normal magical secrets.
Edit: Actually it doesn't work for normal magical secrets too, but I know for certain you can replace those spells at later levels.