I know that is correct because on our last trip the Immigration Officer was very friendly and he commented on how many times we had visited the States. We said we just love finding new places and my husband said he'd like to move, given half a chance. The IO said you realise you can come in 90 days and then leave and come back for another 90etc and we said we couldnt at the moment because of work commitments and he said well at least when you retire you have that option and specifically said and if any other Officer tells you that you can't be done, ask him to show you where it's written that you can't, and he wont be able to because it isn't.