It's not. You get a solid 80% through oral administration, so even if it were a tad higher you're just splitting hairs. Compounded by the fact that most of what composes a pill of adderall is filler which is probably gonna going to block absorption of the active ingredient (significantly but not completely) which in turn will lead to you swallowing a portion of the drug. This kind of renders the argument over the possible 20% bioavailability difference inapplicable. Also swallowing the pills whole combined with the antacid might negate the difference in bioavailability, maybe not in strength, but certainly in duration of effect. I, unfortunately don't know what the oral BA of d-amphetamine is so I can't really complete this answer, but this is the best I got