Ratios analysis based on disposal of Sco from Pco

I wanna to put question relating the mentioned subject but I can not be successful.

Hi my Dear and Fantastic Tutor, I have a question relating to ratio and the question has been taken from Bpp text book page number Greenwood

Greenwood is a public listed company.On 31 march 20×7 Greenwood sold its 80%-owned subsidiary-Deadwood-for $6 million.The directors have been advised that the disposal qualifies as a discontinued operation and it has been accounted for accordingly.The disposal proceeds were not collected untill after the year end.

Note:The carrying amount of the assets of Deadwood at 31 March 20X6 was 6.25$million.Greenwood measures NCI at share of net assets.

20X6 P/l

Revenue-21200
Cost of sales-(15000)
GP -6200
Operating expense-(2450)

3750
Finance cost (250)
profit before tax-3500

20X7 P/L
Revenue-27500
Cost of SAles-(19500)
GP-8000

Operating expenses-(2900)

5100

finance cost-(600)
Profit before tax-4500

20X6
Equity each 1 $-10000
RE-2750
NCI-1250
Non-current liability
5%loan note -5000

20×7
Equity each 1$-10000
RE-4500
Non-current liability
5%loan note-8000

SOlution

20×7
ROCE

4500+400(finance cost shown for 20X7 only $400,000 is loan note interest(8000*5%=400)/14500+8000-6000(disposal proceed)=29.7%

here is disposal proceed deducted because Greenwood does not have any Sco deadwood

20×6
ROCE

3750/12750+5000-6250=32.6%

but here why do i deduct carrying amount of assets of Deadwood?if it was deducted how comparison could be healthy?it both cases it looks like in 20×7 DEADwood sold that is understandable but in 20×6 it exists but it deducted like they excluded it.

in both cases without Deadwood.At least it should be included(not deducted 6250) in 20×6 to make relevant comparision between 20×6 and 2ox7.