That is a good question. My guess would be because Yellow and ABF are now under separate contracts with different contribution requirements for each employer. I am not 100% positive, but I am pretty sure that ABF employees are only allowed to make up pension contributions on their own behalf if they are on an approved "Leave of Absence" per the contract. In other words, if an employee wanted to pay out of pocket for let's say 4 months of pension contributions to reach a certain payout goal to be able to retire 4 months sooner, I don't know of any contract language that would allow this. Not to mention the cost as it would be roughly $12,000 per year out of pocket for a Yellow employee to reach full contribution rate combined with the rate currently paid in on their behalf per their contract. Again, I am not 100% positive, but I am pretty sure that is why.