Firstly on Sharptooth recommendation, Harry had chosen a Goblin called Hundook, to manage his Black and Slytherin accounts, while Sharptooth would manage Potter, Gryffindor and Peverell accounts.
Not to mention the fastest record for someone to level is one month which was set by ais from Loki Familia, so the gap between both of these records is very big
honestly it's a good book but the character doesn't behave in one way and even sociopaths like myself can tell that he's bipolar and prone to bouts of rage for no apparent reason it's honestly frustrating reading it