Yep, your read it correct
I was returning from Malaysia on 17 Mar-14 around 6pm, nearing 7pm. So while in queue over at the Singapore customs side, I saw a convoy of ~ 7/8 Lamborghini's go past on the left most lane, which spirals down toward the lorries/bus/vans clearance block.
Is there something about that make of cars that require them to clear customs via such a different block?