@dust2dustI did not see a change in the International minutes we had until 0ver 20 minutes later so yes, it looks like the real answer is, that as long as you have some kind of "minutes" left elsewhere , then PM will not cut you off during a conversa...
Not sure if this is the actual case. My wife's plan says it is all used up as of last night, but this morning she called me on it, and we talked for over 3 minutes. We do not have the $5 add on, but we do have an international minutes add on, however...