Difference between Over Again and Once Again

OVER AGAIN vs ONCE AGAIN: ADVERB

In due course, Just now, Eftsoons, Recontinue, One after another, In due time, In return, At length, And then, At one time, Time and again, Anew, Once more, Once again, Again

Againward, For one thing, In due course, Just now, Eftsoons, Recontinue, One after another, In due time, In return, At length, And then, At one time, Time and again, Anew, Again

Was transferred to so many different departments and went over the same story, over and over again.
He thought things over and over again and when the first outburst of anger was over.
So I sang in the car for like a month, the same song over and over and over and over again.
It was over and over and over and over and over again, with a purpose.
Review means to look over again, think about again, or revisit.
We keep asking them to make their case, over and over and over and over again.
Over time, some patterns emerge that result in modifying the same clauses over and over again.
Why would you parse over and over and over and over again and again and again.
Let me say again, there are several checkpoints at which we could play this record over and over again.
Here we are again in a long hearing, all afternoon, questions over and over again.

Under these circumstances, once the hospitalized patient elects hospice, there is once again an avenue for daily hospital reimbursement.
Once passed, these issues are cast in stone unless they can once again go before the voters for remediation.
The story changed on there side many times once again no evidence and he won again like some freaking game.
Butler had followed them there, once again steals Jirachi, and tries to take its power again.
Once the eye passes through, winds and storms will increase once again.
San Francisco muttering, once again, NEVER AGAIN, NEVER AGAIN.
Mitch Rapp you once knew is now once again changing.
Once again, Nancy faces two puzzling mysteries at once!
But if they start drinking again, the levels will once again increase.
Could you please lay that out again once again for us?