Dressing for an interview can be so complicated these days. Given that one of the main objectives of the interview is to check out the fit between the candidate and the company, I think you are wise to think about why "business casual" is suggested instead of "business dress". If the corporate culture is quite informal (polo shirts, khakis, denim), showing up in a more formal garb might make you seem unapproachable or unwilling to adapt to the requirements of the position. I think the key here is to dress for the requirements of the prospective job/organizational culture, and not on what, in theory, ought to be an appropriate interview outfit.
To my eye, you look wonderful in both of your outfits, but they do have a more formal, reserved air about them. Since many interviewers read quite a bit into the primary impression that they get when the candidate enters the interview room, it might be worth thinking about it from that perspective. Some of us just naturally appear more formal and reserved, even in our casual clothes, while others can struggle against looking too youthful even in a business suit. What we choose to wear can reinforce or counter our natural tendencies so we can control that primary impression to some degree.
