I've never lived in the mid-west or the New England region of the USA. Maybe it's a regional usage (I've lived in Florida, Texas, California, Colorado, Utah, Oregon, and Washington). I'm not sure where I picked up my usage from. My dad is from Colorado and my mom from California. Maybe I picked it up from one of them ;-)
I'm from New England, I grew up with the informal definition and was super surprised when I heard the formal one.