Example 3: Other wasting asset -Companies

Hello Sir,

I was trying out the example 3 of the non chattel wasting asset.
The reduction for allowable cost computation states:
12/30 x (25000 – 1000)
Bought on 1 March 2007 and Sold on 1 March 2021.

Should the period of ownership be 14 years?

Please advise.

Thank you.

Sincerely,
Maria