10 boss drops is the most vague term you could use
Theres 9 boss drops all with varying values and thats not even including enchants. 10 forceful mino hats wouldnt get you any ss but 10 strong oaths easily could (even tho nobody actually has 10 strong oaths as far as ik but its just an example)
He will have to specify what boss drops he has and what enchants he got on them and then we can decide if hes underpaying or not