Overwriting addon macro config not working

[mydea]

I have an addon with a macro config like this:

module.exports = {
  name: require('./package').name,

    '@embroider/macros': {
      setOwnConfig: {
        mockUsername: 'jane@example.com',
      },
    },
  },
};

And an app using this addon with a config like this:

 '@embroider/macros': {
      setConfig: {
        'ember-cognito-identity': {
          mockUsername: 'john@fabscale.com',
          other: 'test here',
        },
      },
    },

Now if I do this in my addon:

console.log(getOwnConfig().mockUsername, getOwnConfig().other);

it will print out: "jane@example.com test here"

So it seems that any configuration from the addon itself takes precedence over configuration in the app, which I guess is not how this is supposed to work (at least that was my understanding)? If that is not how this is supposed to work (e.g. addon config should not be overwriteable), how would you go ahead providing default values for an addon?