Hmm.. I haven't noticed any difference between using terries and using their MCN's. I only have a small stash now (sold what didn't suit and have only been left with two hard to get types!) for two girls, so we usually get 2 days MCN's, and one day of terries. The girls have rashes from teething at the moment, 9 month old is getting another tooth, and 2 year old is getting her top molars - so its hard to say its coming from the flats - cos it only turns up after they do an awful poop.