Keg and I have had the discussion about Singapore ATC before, yet I doubt if Keg has even yet done as I suggested and visited SIN ATC at work to see for himself that, if anything, they would prefer to disadvantage an SQ aircraft than a visitor. By Kegs own admission he only goes to SIN very rarely. Willadvise makes the very good point that at Changi you can expect a whole lot more SQ than anything else, I got very irate once about being, as I thought, 'stuffed' by another SQ that I thought was both behind and above me, turned out the callsign was only different by virtue of the same digits in a different order e.g. '826' and '862', very pleased my sharp eared FO spotted it in time that the 'traffic' was, in fact, ahead and below.
Keg, I wouldn't bother asking those QF captains if I were you! When I was there many of them had taken their 'super' and gone to SIA, no complaints at all about SIN ATC, had visited the operation and fully understood the workings, found it to be totally fair and, if anything, biased against SQ and I would urge all of you who visit Singapore to take the time to visit ATC, they would welcome you and be pleased to show you how it all works, they are a very professional bunch, much better than my experience of Sydney, for example.
Finally, Keg, you can reasonably expect a .86 747 to be put ahead of a .80 767, or even if you are in a 747, when ATC are trying to put you on the runway nearest to your terminal and SQ on the runway nearest to theirs.