It's both easier and cheaper...
...to leave it universal, and just jiggle the income tax rate / thresholds a bit to balance the books.

If you make it means tested, then someone has to do the test, administer it, ensure compliance, sort out the daft edge cases, defend it in parliament, and generally waste a whole load of expensive legal time and effort that would be better spent sorting out corporate tax loopholes.
( Amish Information Systems hates misplaced, commas, Tue 6 Mar 2012, 13:17, 2 replies)

But they don't.
They literally just need to attach it to your tax code.

There is no 'testing' that would need to be done then.
( scarpe We Stole Bikes, Tue 6 Mar 2012, 13:33, closed)

I've never understood why they have the ludicrous tax credit system
with all it's complex admin and stupid proceedures, when simply altering tax codes could give the same effect.
If you work for the government you're paid, then taxed, then given tax credit. Why not just pay the net amount, once??
(localboy purveyor of pisspoor puns, Tue 6 Mar 2012, 13:48, closed)

plus, you can't be overpaid..
if you earn more above the threshold, more tax is taken off automatically.
(localboy purveyor of pisspoor puns, Tue 6 Mar 2012, 13:50, closed)

That's pretty much what I meant
...since your tax code is effectively just an adjustment to your tax thresholds.
( Amish Information Systems hates misplaced, commas, Tue 6 Mar 2012, 17:51, closed)

I think this is relevant to the discussion
stumblingandmumbling.typepad.com/stumbling_and_mumbling/2012/03/tax-the-middlingly-rich.html?utm_source=dlvr.it&utm_medium=twitter
(Smale is stuffed, Tue 6 Mar 2012, 13:43, closed)