Each year, OSEA include "gain/loss of FAIR VALUE ADJUSTMENT" to their Income Statement. Therefore most propably investment properties of OSEA shown in the accounts are up-to-date and there will be no significant gain, even they go for a revaluation.
A research report resently published by Asia Securities/Asia Wealth Management emphasised that "this is the ideal time to invest in OSEA" (obviously Long-term prospective).
Good Luck !!