Not a FedEx guy, but I have a pension at a different airline. You can't just bump up the annual compensation limit. That number and many others are tweaked by the IRS annually. It is actually $265,000 for 2015.
Here is the link.
IRS Announces 2015 Pension Plan Limitations; Taxpayers May Contribute up to $18,000 to their 401(k) plans in 2015