And I don't know how much he really knows about what goes on here and what AN will or will not do...
The fact of the matter is this: AN ran a compelling campaign in the one-week between the first and second rounds of the election. All of the other candidates pledged their votes to Hashemi which just made AN look more appealing to Iranians who do not trust the establishment.
Only time will tell what will happen here.
Informed Comment: All that said, it is probably true that there was some ballot stuffing by Ahmadinejad supporters. It was alleged by clerical moderate Karrubi, and it is plausible. These presidential elections are the least free and fair since the early 1990s, though all along there has been a problem of the exclusion and vetting of candidates by the clerics. On the other hand, it seems undeniable that Ahmadinejad's campaign struck a chord with many Iranians tired of corruption and economic stagnation. He may well have won the second round even without those 'extra' ballots.
Thanks to Diana for pointing me in this direction.