I think, in the UTP, the task names refer to the average human (Stat-7, Skill-2) attempting the task.
More like skill 1 and taking "extra time", but yeah.
See, impossible is impossible for stat 5-9, skill 1 under the 2d6 flavor of the UTP... 19+ becomes 15+ with extra time, and the stat 5-9 is DM+1 (for 14+) then the skill is a DM +1 (for 13+). You have to be exceptional (skill 2+ or stat 10+) to "do the impossible"... and if unskilled, you cannot succeed.
Using the extra time, DM+2 total...
Impossible: Can't be done
Formidable: 9+
Difficult: 5+
Routine: 1+ (auto)
Simple: (–3)+ (auto exceptional)