Yeah, Aaron crossed level 20 and reached level 21.
After reaching level 20, there was a rank-up quest. Due to the rank-up quest, though he can't level up, the EXP gained would be accumulated till he could complete the Rank-1 quest would be stored.
When he re-entered the dungeon, he had to clear three floors to complete the quest and after that, he cleared the boss.
Since he was already level 20, the EXP gained from Boss wouldn't be enough to reach level 21 but the accumulated EXP from the three floors and his personal boost of 10xEXP due to his talent made it possible to reach level 21.
Now that Aaron reached Rank-1, every level up he should get +10 FSPs and +4 SPs but due to his talent, what he got was +100 FSPs and +40 SPs for reaching level 21.
This means for level up. he can easily improve a single attribute by 100 if he wants to, but that would be a disaster. He would lose control over his body if the attributes are increased quickly.
