Last In, First out yes, but read the COS99. That is off the "redundancy" list and not the seniority list. Which, I am guessing, means the company compiles a list based on where they do and do not need pilots, with the least needed at the bottom (ie. all freighter only FOs). So you could be here 3 years on the -400 and get the boot while a newbie on the 777 gets to keep his job in YYZ and continue to feed his family.
This is my interpretation, if anybody knows for sure, please correct me if I am wrong.
Mayday (a CoS99 freighter only FO hired in 2006)