There's substantially more selling than buying showing on the volume difference bars. Surely this can't be right?

the amount of data the chart is being rendered by; settings maybe?

I'll hazard a guess here, it looks like the ask/bid volume bars study is just another way of displaying the cumulative delta. If that's the case, it represents market orders but not limit orders. With either, it is just a piece of the overall volume picture.

Rrrracer 

I'll hazard a guess here, it looks like the ask/bid volume bars study is just another way of displaying the cumulative delta. If that's the case, it represents market orders but not limit orders. With either, it is just a piece of the overall volume picture.

i would agree....i didn't think of that distinction