Kind of accurate...there is no lock going from the 200 to the 900 if someone wished to do that. But, if for any reason, someone wants to go to a lower paying position a la 900 to 200 then there is a aircraft lock for something like one or two years. The aircraft lock would not prevent someone from upgrading though. I only know this because I know someone who started on the 900 then bid the 200 to get to a DTW base but now that this persons seniority could hold the 900 they cannot go over since they are locked on the 200.