Not to be the "negative" influence, but at the last hub turn meeting, DW stated that the company is NOT interested in "early retirements." Just because it is in the contract, does not mean that it will be offered. FDX will not pay to have guys sitting around, collecting a salary, and not working. FWIW, early retirements costs a company quite a bit of money, i.e., working up a "package" and/or incentive, paying for that incentive, etc.
Do not count on this clause in the contract.