A taxing money situation

Forgive me for getting mildly political just this once (though no promises it won't be just this one time!) but Child Tax Credit... they say "tax doesn't have to be taxing", but the Government are really struggling with basic maths here, aren't they? Don't get me wrong, my maths was never great at school - I got a B at GCSE and every time I got a test back my teacher would pass behind me, theatrically lay the marked paper on the desk in front of me and exclaim "Laura! What went wrong?!". Erm... it was Maths, Miss. It wasn't English, or French or History.

Surely a child lives in a household - whether one, both or neither parent earns money - so whatever money comes into that household is to the benefit of that child?

Now take the current plans - if either parent is a higher rate of tax payer and earns more than £60K per year, Child Tax benefit is stopped for the entire household - even if the other parent earns just £5K a year. So total household income for Family A is £65K. Compare that to Family B where both parents earn £43K per year, total household income being £86K. And yet Family B will retain full Child Tax Benefit.

There's something array there - I'm pretty sure of it. I'm not an economist so perhaps someone can enlighten me where my calculations fall down? But if the folk in Government really can't realise that basic error, how are they going to fix major problems? The NHS, the Police, Pensions, the National Debt... ?! eek!

I've written to my Local MP about this a couple of times - I say MP - what he really is is a glorified and over-paid PA as all he does is pass my letters onto rubber-nosed desk johnnies in and around Westminster rather than review an issue personally, take a stance on it and take measures to tackle it head on for his voting constituents. No, because he's too busy fixing his speeding convictions and messy personal life. My theory on this is, however, that they know they've made a BIG mistake, but it's better for them to hold firm on it and hope no-one notices, than it is to admit they made a mistake and change direction.

I am definitely more forgiving of folk who recognise their error and take action to fix it than those who arrogantly plough on with a flawed plan. And trust me, I don't always forgive easily!

If I'm wrong, and it's been known to happen on occasion, please kindly tell me the actually situation here. Thanks!