Well, it might be that the NFC is specified low-power, enough just to read the tag next to it but there's nothing that prevents it to be a bit more longrange. Actually I would be really surprised if it was even possible to tune the output power so precisely that it would reliably read the TOH tag and at the same time be incapable of reading an external tag. (NFC's designed to be able to read multiple tags in the vicinity simultaneously, BTW)