Question about TIME BACK rage power

[Jamers]

So I assumed that Time Back just warped a troop back to the POSITION that they were standing on during the previous turn (as it says in the game), and that it was basically used to stall enemy melee troops from closing in.

Then I read a thread that described it as the best rage in the game, saying that it was like a resurrection as well, bringing the troop back to its original number of units as well as changing its physical position (thus making it much more useful for friendly troops versus enemies). Can anyone confirm that this is how it works, or just describe exactly what it does? I've been improving it on level ups and I'm hoping I'm not wasting my level improvements.

Thanks in advance.