Ah. Now I see the difference. This is a common misunderstanding that happens when people try to equate bourbon column stills with the grain whiskey stills in Scotland. The stills in Kentucky are much smaller. Some 'products,' if you want to call them that, are vented away at the top of the still, in some set ups, but otherwise nothing is removed except by the process itself. The difference is that the rum, tequila, and vodka stills are much, much bigger and they're removing everything.
This is not strictly a function of through put. An American whiskey distillery will have multiple stills rather than one enormous one. They're trying to craft a taste, not remove all taste.
I get it now, I can see how in an ethanol plant you would produce enough of these what I would call distillation by products to make it worthwhile to capture them.
So, no, for all intents and purposes there is no fractional distillation going on in bourbon production.