Home Office Asset Summary - Cost of Your Home. Do I enter original purchase price or fair market value at the time the home office was placed into service?

I'm entering info about my home.When I get to the 'Cost of Your Home' screen, it asks for Cost of your entire home. I purchased the home in 1986 but put the home office into service in 2002.  The fair market value of the home was much higher in 2002 than in 1986, plus I had refinanced and owed substantially more on the loan than the original purchase price. Can I use the FMV for 2017?