About those confusing practice and qualifying AI results, they say this: "the AI times in such circumstances are calculated based on a ‘football management” style simulation model. Using this model all of the race factors, such as the car, driver, weather, tyres, engine, track conditions, traffic are all taken into account and a lap time is produced. These generated times are well considered and guided by a huge amount of data; they are not randomly generated. Nevertheless they remain simulated approximations using this model."
And on race AI: "We have seen several email and forum threads which suggest that an AI car’s performance is determined by where they are positioned currently in the race, or where they are in relation to the player which absolutely isn’t the case."
Nevertheless, there's a patch on its way. Read the full thing here. (I've actually had quite a lot of fun with this, in the meantime. It's a pretty good racing game...)