A friend has asked me for this advise & I couldn't help. I have not travelled on SIA A380 business class myself. Info: my friend did experience SIA long-haul spacebed once. Acting impulsively, my friend bought a LHR-SIN-LHR business class ticket at slightly over £2000 (thought it was a good offer) & since has changed dates, creating unnecessary frustration now being waitlisted (though optimistic about confirming).
Anyway, miss piggybank poured out saving for the airfare and now has second thought of buying a confirmed return economy class £500 & sending the business ticket for a refund. In return £1000 could be used for something tangible. I said to my friend the refund would nearly cost a quarter of the airfare & that's where the trouble is.
I could only offer advise the pro and con like not losing 25% penalty or having £1000 in your hands. Other than that, is A380 business class worth the opportunity cost?