Chapter 7 in OT notes Exam Prep Question Page 35

Question: Shea Co. acquired an office Building for $25m on 1st January 20×2 with an estimated useful life of 20 years. On 1 July 20×8, the building was deemed impaired as its value in use was estimated to be $14m. At that date, the estimated useful life was revised to 10 years.
My problem: The Depreciation charge of 6 months after the Impairment in the answer is (500) while the way I have calculated it gives me (700)
The way I solved the problem:
Cost 25,000
Acc. dep. -7,500
C.V. 17,500
Dep. (25000/20×6/12) -625
C.V. 16,875
Impairment (16,875-14000) -2,875
C.V. (1.7.08) 14,000
Dep. (14,000/10×6/12) -700
C.V. 13,300