Not sure how one can view "someone like the son of man" the same as the Ancient of days. He approached the Ancient of days and kingship was bestowed upon him.
Daniel 7:13, 14 (OG) I was watching in the night visions, and lo, as it were a son of man was coming upon the clouds of heaven. And he came as far as the ancient of days, and the attendants were present with him. And royal authority was given to him, and all the nations of the earth according to posterity, and all honor was serving him. And his authority is an everlasting authority, which shall never be removed-- and his kingship, which will never perish.
--- Daniel (TH) I was watching in the night visions, and lo, as it were a son of man coming with the clouds of heaven. And he came as far as the ancient of days and was presented to him. And to him was given the dominion and the honor and the kingship, and all peoples, tribes, languages shall be subject him. His authority is an everlasting authority, which will not pass away, and his kingship will not be destroyed.
(Dan. 7:13, 14 NETS)
Theodotion based his text on the MT. It became the standard Daniel text. Most modern scholars believe the OG version to be based on a different, unidentified text because of the differences. Few MSS remain with it as their text.
However, it seems as though "son of man" was a common designation at the time. Gabriel refers to Daniel as such (cf. Dan. 8:17). Of course the context is different. Same goes for Ezekiel. In the vision the person coming before the Ancient of days is referred to "someone like a son of man," quite apt for a heavenly setting, where a human would not survive. Makes sense to me.