"In later Greek literature, Hyperion is always distinguished from Helios; the former was ascribed the characteristics of the "God of Watchfulness, Wisdom and the Light", while the latter became the physical incarnation of the Sun."
When cosmogony meets theogony there is generally confusion as to just who is who. There often appears to be three levels : 1) The Principle 2) The Cosmic Entity 3) The God, either heavenly and/or earthly. And, often all three have the same name.
Ancient Greek is often confusing. Grab an interlinear version of the Bible and compare the original Greek with the English translation and it is obvious that some poetic licence is at play. This, does not assist those who respect exactitude in translation.
Also, if one is to Google "Greek Gods" and pore over the resultant genealogies, one finds many discrepancies as to just who is who once again.
That aside, the link below is of a most interesting nature and may be the answer to your question - The Sun Behind The Sun.