SIA Cargo has always been a bad deal compared to mainline which is why it was separated years ago from mainline.
Lots of positioning, no pay for it, reduced annual leave,ID tickets reduced.etc etc
One always needed at least 70 hours per month flying to make reasonable money which cargo guys did not often achieve as positioning does not count.
Once you have done a few positioning trips to say SFO/LAX straight through via SEL/HKG in the middle seat of economy surrounded by the great unwashed of the world the job takes on a whole new perspective.