I'm not at all disagreeing with that. (I wasn't sure if you could add HBO I thought you could, doesn't really matter then) My point is, it isn't that there is a minimum where you can get HD free. There is a minimum where you can get HD at all. (Short of locals/freeview etc) If there was a choice, you could get HD for the channels in the Welcome package but had to pay $10, then I would agree you can't have the HD free for life in that package. You can have it, but there are no channels to apply it to.
HD for life doesn't give you HD channels when there are none being offered, it gives you them for no additional charge when they are offered in HD. Similar is NBA TV in the Sports package that is in SD there but HD in the package it is in. (Top 200 or higher) HD for life does not give you that channel in HD if you only get that channel in the sports package.