Your assumption is correct, but sometimes a raised/hollow stage floor can vibrate too much and give you a mushy sound instead of more bass. If the stage is blocked by a closed in bar/counter, then you have to get everything UP, above the counter. If you're playing for 100 or so, I would think your regular set-up would be just fine. Placing things on the bar would probably be like putting things on chairs or stands. Definitely get your mains sound UP- at or above the counter, unless you have a small/close crowd and don't want to blast them out with direct sound.