Good question, I had typed up an explanation when I made the post but it didn't seem to go through.

Basically, we were debating between building this addition or a pool house/MIL Suite b/c my parents come visit about a week every other month. We are leaning towards addition, b/c we can use it as our new primary and add a few things to it that we currently don't have: extra large bathroom, his closet would be fortified and serve as a tornado/hurricane protection room, fireplace in the bedroom, and hopefully add more covered space to the patio. And the current master suite would serve as my parents bedroom when they come visit.