Even considering other possible theories, one that presumes he continued to stay in Shimousa in spite of the reward grants in Mutsu and another that presumes that he relocated to Mutsu, the existence of Tanemochi is still doubtful due to unreliable data of the family trees.
そうでなくとも、国分胤通が陸奥で恩賞を得ながら下総に留まったとみる説はもとより、胤通の移住まで肯定する説も、系図の詳細を信用しているわけではないので、胤茂の実在性にはやはり疑問が残る。