As AriaMagiYoshiko said, He does not allow reprints unless it is uploaded on his official account.
He seems to only use his youtube to upload videos relating to his professional singing , opposed to his personal singing which is why the videos on his youtube are not uploaded onto Nico Nico Douga account which he uses for his personal singing. Its common for profesional singers to have their own seperate youtube channel just for their professional music, its to keep their personal work and professional work seperate.
Take Piko for example, he uploads to NND but he also has a seperate youtube account just for his professionally released songs, and thoose songs are not uploaded to NND either.
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