sorry but I can't help ya with that issue because I've never tested it.

only think I'd like to say:
if you're doing this in an instance (leaving the party, tagging the mobs, killing the mobs with your crew and rejoining the party to avoid getting ported out)
then it is an exploiting mechanic which Blizzard doesn't tolerate (best example is Athene which tried to get first lvl 80 when WOTLK launched and got set
back to level 70 after Blizz saw that he was exploiting the instance mechanic).