I specifically said business class on 1-2-1 configured aircraft. Which type of metal, which route did you get business class ? To take MEL-SIN as an example, I can (often) see inventory on the 773 and now the 332, but never the 77W or A380. For SIN-Europe or flights I have never seen availability using UA miles to LHR, MXP, MUC, CDG, ZRH, BCN, MAN or AMS. However occasionally something pops up for IST, FCO or CPH on the 777-200ER. I wonder if that will stay now that they are being upgraded to the 1-2-1 product.
As an aside, SQ inventory (using KF miles) often opens up about 2-3 days out, so I am not surprised about getting flights with 8 hours notice!