Reversal of Impairment

Dear Sir,
I have a question concerning the Plothera Case in BPP Kit.

Plethora owns a retail business, which is considered a separate cash-generating unit, which suffered a difficulty trading period in the previous year and was subject to an impairment review at 31 December 20X8. At that date, an impairment loss of $160,000 was recognized. The directors of Plethora Plc believe the indicators of impairment have been reversed by 31 December 20X9 and wish to reverse the previous impairment to the maximum extent possible.

Relevant financial information in respect of the retail business is as follows:
CV at 31.12.20X8 before impairment:
Assets
Building 900
Plant and equipment 300
Goodwill 40

Impairment loss at 31.12.20X8:
Assets
Building 100
Plant and equipment 20
Goodwill 40

Estimated FV at 31.12.20X9:
Assets
Building 925
Plant and equipment 310
Goodwill 60

CV at 31.12.20X9 had no impairment occurred:
Assets
Building 875
Plant and equipment 290
Goodwill 40

Let’s take a Building as an example:
– Building Recoverable amount at 31/12/X8 = 900-100= 800. Since it is less than the CA, we should record the Building-CA on the SoFP at 31/12/X8 = 800.
– At 31/12/X9, the recoverable amount was higher -> Indication of reversal. However, we can only reverse the the maximum of carrying amount at 31/12/X9 if no impairment occurred (which is 875)
– In the BPP answer, the reversal amount = 875-800 =75. However, I think the reversal should have been higher as we had to deduct the new depreciation from the CA of 800?

Could you please kindly explain to me why the depreciation for the year X9 was not deducted from the CA when we reverse the previous impairment loss?

Thank you Sir!!!