The inverted overflow is for us that don't want their knees sticking out while our feet or being worked over by the foot jets. (and I wouldn't get a tub that didn't have foot jets and the back jet(s) are nice. Some of those side jets just gouge a hole in your hip and can be painful. I spent a lot of time in showrooms (to my wife's embarrassment) climbing into and testing tubs to make sure they fit my back when sitting. Some name brand jacuzzis were very uncomfortable in the angle of the back. Also the 6 footers were too long and made me want to slide in. I needed a shorter one to hold myself above water and about 5.5' would be just about right and also keep my knees down but couldn't find one.