Is this a promotional fare that it has such restrictive rules? I would have just booked an ex-South East Asia or ex-China ticket.

Example:
MNL-ZRH-MNL is only USD 2,984 and allows free re-booking with no time limitation (only fare difference if any) and it's not even a promotional ticket. You also get more miles and club points which is a bonus.

PS. I find that airlines are very sneaky in hiding these restrictions in the really long fare rules that aren't reader friendly. If you are used to travelling or have experience then it's no problem; but for novices and beginners then it really is confusing.