The pill must be a Tier 5 immortal pill; he could only concoct unique grade Tier 5 pills. However, unique grade Tier 5 pills alone might not guarantee him a spot in the top 50. After all, most of the people here were Tier 6 Pill Kings and they were concocting Tier 6 pills.
Moreover, during the first round, he didn't pull his score away from the rest. A 6 to 7 point gap in purification was huge, but the moment pill concoction was added in, then it wasn't anything. If a batch of high grade Tier 6 pills was scored at 80 points, then a batch of high grade Tier 5 pills would only get 30 points.
Perhaps concocting an entire batch of unique grade Tier 5 pills might be equivalent to a batch of high grade Tier 6 pills. However, this was just a 'might’, Mo Wuji didn't know the exact scoring criteria.
