Maybe an even better comparison is the intake port volume of heads. Different heads can have the same intake port volume (say 160 cc) and would therefore be considered suitable for a certain type of engine (say a 302) and performance goal. Yet the heads have different flow numbers.
Like with intake ports, it's the flow velocity rather than the flow capacity that makes a carb or head suitable for a certain engine. The flow velocity is largely determined by the dimensions (port cross area, throttle blade size....) which makes both carbs/heads suitable for the same engine, yet the flow capacity of one head/carb can be better than the other.
At least, that's the way I see it.
A question for the Demon Tech: Would it be possible to use Holley bowls on the Demon carbs? Call me weird, but although I like the design aspects of the Demons, I care more for the classic Holley look. Not that the Demons are ugly, but I just like the 60's look better.