first of all, your tank was in half DPS gear, so technically you had 2.5 DPS
second, this has been done back 4 months ago with black hole gear, so comparing it to that you guys didnt do anything special
third, the objective is to CLEAR it with 4 ppl, doesnt if 3 of the ppl are Dps or not.
i doubt u ppl even have your warstalker titles, at least ur not going to get with this attitude
Let's just let it go. We're arguing on the internet about achievements in SWTOR, one of the easiest MMOs on the market.
What else is there to do?