Sorry, I have not read everything.
On the official page, the 4-sentence description on how to qualify is (perhaps deliberately) vague.
They say when the 12-month period ends (after 12 months OR when you reach the "next" level, whichever is earlier). Strictly interpreted, this means that when one re-qualifies for the same status as the current status, one never reaches a "next" level so the period is the full 12 months.
They do not state explicitely when the so-called 12-month period starts for the first time in this program.
They state extra points are carried over when the timer is reset (Any XP you gained above the required threshold will be yours to keep.) but it is not made clear if this also happens at the normal end of the 12-months period if one does NOT achieve the "next" level by then.
They do not state explicitely for how long the status is granted. I this thread I see 12 months (plus 3 months), where does this information come from?