Totally agree 10 mins is way too short. I recall it was 15 mins before and it went down to zero
If it takes you more than 10 minutes to exit the garage when you realize you made a wrong turn or don't need to park in there, than you have larger problems than having to pay a few bucks...
Same with if you're picking someone up. Either they're waiting for you in the garage near the elevators, or you make them pay a couple bucks. Ten minutes is plenty to get in, pick someone up, and get out. Or check to see if there is parking, realize it's packed, and get out.