He is unable to provide you clear or valid data simply because there is none. In the cast of this 520 iLvl mage, Frost sims highest for him, unless he has weirdly itemised gear(hit/crit HC Scenario gear, etc.). I know that your counter argument will be "SIMCRAFT IS INACCURATE", but if simcraft confirms common sense then that's good enough for me.
Besides, how can you even speak of Frost's performance in a Heroic environment when people are unable to enter Heroic, or down Heroic bosses in ilvl 560-570 gear? As long as we are talking about Frost's current situation then the only thing that matters is how our ilvl 530 average frost mage performs in normal modes.