Balancing adjustment on the main or special pool

Hi, I have a doubt in example 4
plant sold for £8600 and it’s purchased cost £10,200 why didn’t you take in to the Pool column this £10,200/-?

May be I guess Because of there a AIA(£1M) £10,200 it will be make it zero
is that you didn’t brought in it to the pool Column

Or any reason there?

If that plant sold for Higher than cost amount what will we do ? I mean

Plant sold (original cost price £10,200) for £12,000