With all due respect, I see two issues here, [MENTION=311]upsidedown[/MENTION]. First, the transmission behavior is tied in to the "learning" mode of the computer, not just in Smart drive mode, but I think in all modes. Depending on how you drive most of the time, the shift points vary and change over time.
Second, since Kia must warranty this car for 10 years / 100,000 miles in the U.S., it is not unexpected that they will guard against potential abuse, over-revving or lugging, and anything that could potentially cause expensive repairs that are not their fault because the car was pushed beyond its design parameters. My G8 would also automatically downshift in manual mode, and I don't know of any transmission that doesn't other than the 6-speed stick in my GTO.