Sector caveat
Do not compute Standard FCF for a REIT. The depreciation add-back is so large that FCF is misleading; AFFO is the industry-standard alternative.
NAREIT FFO formula
FFO = Net income + real-estate depreciation - gains on sales of property.
AFFO derivation
FFO$1,200
Less: recurring CapEx (maintenance)($180)
Less: straight-line rent adjustment($45)
AFFO$975
Why real-estate depreciation is large
Office and apartment buildings depreciate under MACRS over 27.5-39 years, but market values are typically flat to rising. The GAAP charge is therefore a non-cash bookkeeping artefact. Damodaran addresses the real-estate exception directly[Damodaran].