Pro-sites: how on earth do I use this functionality?

I’m trying to specify the quotas for the different levels:

But I cannot see how on earth this works? When I select a different level, at the top, I would expect to be presented with the current settings for that level. Instead, it remains unchanged – regardless of which level I choose. It is impossible to check the current settings, and make changes to the current settings.

Am I missing something?

Kind Regards