Based on some superficial research and a lot of painful experience, I want to say that maida and 'all purpose flour' are not the same. Maida has some minor percentage (I don't know exactly what %) of tapioca flour mixed in it, making it more elastic when made into a dough. Maida is also quite finer and whiter than 'all purpose flour'. Although the difference may seem insignificant, you'll feel the difference in the outcome of many dishes; especially when you try to make South-Indian style parottas. So all you cooking enthusiasts please start making this distinction in your recipes. Please don't continue with your dubious ingredients list and give others a hard time.
What prompted this post? The Patel guy who owns the Indian store where I buy my stuff, sold me a bag of 'all purpose flour' crudely labeled as maida. This is not the same pack I usually buy, so I ask if it's actually maida? He first argues that they are both the same. I almost refuse to buy this new bag because I get a strong feeling that, with the increase in wheat price and everything, they no longer export maida from India. And this guy just made his own little bags out of the regular 'all purpose flour'. Anyway, I bought it, got it home and got screwed up 'ceylon parottas'; disappointing my Sri Lankan friends and embarrassing myself.
PS. Both 'all purpose flour' and maida aren't the best food products for "healthy" eating.