-It, also, says that when smoked together, the effects are dramatically worse.

And when cannabis and tobacco are smoked together, the effects are dramatically worse.
Oh, forget it. I can't even back anything up that they say.

I'd think that any additive, to Herb, would degenerate it and make your "high" not last as long, or be fully capable.

Kind of like your brain. If it's full of statistics, then it won't be as pure when you throw a quote in there.