If you are asking how a one person working family with a SAHM gets so much FTB? Your DH must be earning around 80-90k ball park to only get $100 p/t? A family on say 70k would get more obviously. Then you will only have one child. Someone with say5 kids with a partner that say earns 50-60k (which is still about 4 times more than a single mum) would get about 800-900ish per fortnight. That's a whole income of a single mum with one child. Obviously it costs way more to feed and clothe 5 kids than 1, but my point is that the govt is spending the same amount of this hypothetical family, as the single parent one.