I am not sure about any letter sent to MAA for a recall, but if this T/A ratifies, it will because of folks who want out. This proposal is very concessionary and keeps wages down for another 7 years (basically a decade if you count from 2002).
If folks believe they can't do that for the next 10 years of their working life, with no pension, or enough extra money to put in a 401K, they will opt out for other jobs that allow for weekends and holidays off, and a life that they can finally share with their families.
If this assumption takes place, many senior reserves will hold permanent lines of flying for the first time. Everyone will move up, and there maybe a "recall" finally for the INVOLs who want to come back to "mainline".
Those on MAA may opt not to come back as they know they will be reserve for a very long time and displaced. So who knows at that point.