Except for peak holiday times, you usually have to wait until barge has several vehicles on board before it leaves so there is plenty of time to to check so can't see any reason to increase prices.
Usually the ramp comes up as they leave the beach and they have to lower front one as they approach beach for better visibility.
I think is is now $120 return because there is no competition. It was only $80 not that long ago until Kingfisher Bay mob pulled their barges out and left it to Mantaray. Amazing what competition does. I use Kingfisher barge from River Heads as it is only 5klm from home for similar price as a local but normal price is $165 return.