yankel> there is no difference between a ben torah and talmid chacham , however ,
by a typical gemora, it seems that: ben Torah is someone who reliably knows regular daily halachos. In osme cases, he may NOT need additional chumros that will keep amei haaretz from mixing up permitted from forbidden. Talmid Chacham is someone who can reliably answer shailos on the maseches he is studying. Chacham is someone can answer sheilos on any topic. So, T’Ch is a step over ben Torah.
But to the topic: did I understand the reference correctly? It seems to be saying that this is what some do, not a strict requirement? And there is a maase that seem to contradict: young Tsfas Emes was learning late at night and not fresh in the morning. His grandfather, Chidushei Harim, gave him some mussar. Hevrusah wondered why Tsfas Emes did not explain that he was learning. He answered: and what – miss an opportunity to get mussar from my grandfather!? The implication here is that learning at night is a good excuse.