Real value of IHT nil rate band to fall

John_Pierpoint

3.13 Inheritance tax allowance — The inheritance tax nil rate band is frozen until April 2015.
The Government has announced that from 2015-16 the consumer prices index will be used as the default indexation assumption.

http://cdn.hm-treasury.gov.uk/2011bu...n_overview.pdf

Ah is this the somewhat complicated calculation that I think it is.
I wonder how one words a will to comply with this:

3.40 Inheritance tax – reduced rate — The Government has announced that a
reduced rate of inheritance tax (IHT) will apply where 10 per cent or more of a
deceased’s net estate (after deducting IHT exemptions, reliefs and the nil rate band) is
left to charity. In those cases the current 40 per cent rate will be reduced to 36 per
cent. The new rate will apply where death occurs on or after 6 April 2012. The
Government will be consulting on the detailed implementation of this measure and will
issue a consultation document before the summer.

Ah is this the somewhat complicated calculation that I think it is.
I wonder how one words a will to comply with this:

Wealthy single cat lover leaves 1,000,000:

1,000,000 minus nil rate band of 325,000 = 675,000 taxable @ 40% = 270,000 tax payable.
Let us leave something to the cats home.
1,000,000 minus NRB = 675,000 minus 100,000 cat bequest = 575,000 taxable @ 36% = 207,000 tax payable.
1,000,000 minus NRB = 675,000 minus 61,364 ..cat bequest = 613636 taxable @ 36% = 222,098 tax payable
So leaving a bit over 61K from a million estate to charity saves about 48K in tax.

I have a feeling I have misunderstood what is intended.