FFF: Level

This guy, Dion, is obsessed with making things level.  It is insane to me that he bought a one hundred dollar level when you can get them for maybe twenty dollars realistically.  The author states that when the wife is going pee, the floor is slanted toward the bathtub.  Does this mean their house is slanted, because everything needs to be leveled out?  I like the ending though.  The level shows that with her pregnant belly and his knees, it is level.  It maybe symbolizes them.  They level each other out.