Let me also point your attention at the fact that by writing in a subjunctive mood ("If one were to code these cases as occupations,") thereby not endorsing the thesis of their occupation. He also does not state this "occupation" ended in 1989, his point is that the only strict date we can speak about is 1989, because after that date it is impossible to speak about any occupation. In any event, since he does not include the Baltic case even as a hypothetical example of occupation, we can safely conclude that he does not consider the Baltic states as occupied by the USSR.