Er, Poccil, I think you're thinking of Echoed Voice. Round is the move that doubles damage if multiple party members on the same side use it on the same turn, while Echoed Voice is the does-more-damage-next-consecutive-turn move. So unless this is a double battle and both of them are using round, then it's no big deal either way.
...so did they both use Round or not? Seeing as if that varied it'd skew results, yeah.
Dream ability hoarder extraordinare!
Breeding up dream world ability breeders on request since... whenever. Can't guarantee good IVs though.
Pokémon Black 2 Code - 5072 1749 8695