leewan,
If your theory holds, then it doesn't bode well for SFJ, SFG, or SFD; all of which are, by MSN, senior to SFA and SFB.
I rather think that this trade out, or turn over is more driven by who actually owns the ships combined with who wants to stay in the cargo airlift game and who wants out. I also know that Evergreen BUYS aircraft it's never leased an aircraft to my knowledge. Could be an important clue,,perhaps BanC of America wants out of the freighter leasing game and the attrition ends here. In any case, if your paycheck is signed "SQC", best you keep a pulse on ebb and flow of the tin.
Cheers