I would agree that she is a master of understatement and situational irony, but not a master of the other forms of irony (sarcasm, overstatement, and dramatic irony).
IT is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife.
Austen's irony is very, very subtle. Her satire is parody, or Horatian satire, and when it is held up to the mirror of reality, it looks very similar. Her comedy produces thoughtful laughter, not outward, side-splitting guffaws.
Yes, comedy is the most realistic of the dramas, but somehow Austen's comedy is so realistic that it seems like romance (melodrama). There is little exaggeration (hyperbole) or caricature: all is done in moderation, tastefully. Her themes are not about life and death; they are about the hypocrisies of social conventions. Her villains are never villains; the suffer from only peccadilloes instead of deadly vices.
Also, her irony deals with the social institutions that were conventions of her time, so the irony often goes unnoticed because today's society is not as formal and stratified as hers.