My Suggestion is the following:

Some reason someone set the one setting to 7 but they did turn down the other option correctly. I recommend setting Light Level to 0 (where mobs would spawn.

You go from this:

To this the new range:

If you just wanted it because you wanted more light, that is fine. Just a suggestion to help teach and show players the new range of where mobs would spawn now. Great for saving torches :)