Quick Willow is merely pointing out the craziness of the current (new) requirements.
Whereas before it was based on disposable income, now it's based on actual income.
So.... for example, if you earn £15,000pa, no debts, and own your own house outright, then you've basically got a disposable income of £15,000 to support yourself (and your loved ones).
.... if you earn £18,600pa, have lots of debts, and pay rent/mortgage, then perhaps after these deductions, you've only got a disposable income of £3,000.
In the old case, the ECO would look more favourably at the first scenario.
Now however, earning £18,600 is the measure ........ not how much you've actually got to live on. So the guy earning "just" £15,000 will have his application rejected.
Totally wrong in my opinion ..... and let's wait for the various legal challenges.
Hope this clarifies / explains the point QuickWillow was making.