PHB said:Overlapping Durations: If a target is affected by multiple powers that have the same effect but end at different times, the effect with the most time remaining applies.
"Save Ends" is one of the listed durations. So if you're hit with the same (save ends) effect multiple times, there is no overlap in duration. One save clears you.
Odd, that rule states the opposite.
If one save ends on round one and one save ends on round two, "the effect with the most time remaining (two rounds, not one) applies".
Nowhere in that rule does it state that the effect with the least amount of time remaining (save on round one) applies.
The same type of duration does not imply stopping at the same time.