i'm not sure if that lower spoiler doesn't do anything. dont forget the flow comming of the C pillars is going inwards, so the sides of the lower spoiler will have some effect. but even so perhaps turbulet flow is not beyond guidance.
also it reminds me of the old citroen ax wich had a spoiler like projection in the same place and a much steeper rear window
the AX has a Cd of only 0.31 wich is rather great for a tiny hatchback so there must have been quite some earo research on it. this spoiler was actually part of the metal hatch so they must have been pretty sure it was doing something right as a flat trunk would have been cheaper and easyer to make.
edit:
come to think of it this car looks very similar to swift/metro's so this sort of thing might be wort for metro owners to look into.