In the NWP, we use very specific language and examples. From our constitution:
"Draft picks may be traded up to 2 seasons in advance. For example, in the 1977 season, teams may trade 1978 or 1979 draft picks. During the 1978 draft, teams may trade picks for the current draft, or for the 1979 or 1980 drafts, etc."
From this wording (which I wrote), "2 seasons in advance" is clearly meant to indicate the next 2 drafts. So if I were to see the words "1 season in advance" I would assume that it means ONLY the very next draft. I can see the ambiguity here - which is why I spelled out with examples exactly what I meant - but absent such clarifying examples, I would assume the commissioner meant interpretation (A) in crazystengel's original post.