Does anyone know if there is a difference between "net carbs" and "impact carbs"?

My understanding of net carbs is that, for example, spinach has a total carbs count of 14g but 6g dietary fibre, then the net carbs is 8g (and those are the ones that count).

I was at GNC looking at the various protein bars and the guy there kept saying "Yeah, but the impact carbs are only...." and I didn't want to look like an idiot...so...I'm asking here (where I may look like an idiot but at least it's not some really buff dude staring at me with thoughts of selling me loads of expensive stuff that I really can't afford.)

Thanks