IFRS allows companies to adopt fair value measures of their assets. It is advantageous for owners with older properties to account under IFRS this way their leverage ratio will be much better. Also I think in this cycle where commercial real estate have been clobbered you will see many years in the future of up revaluation of properties and steady increase in book values.
The accounting changes will move BPO book value from $9 to about $14 making Price/ book value less than 1.
Also they will be compare more favorably now that leverage is reduced. Most analyst do not like BPO because it has higher leverage ratios compared to other office owners.