this 747 retirment has become a funny game delta is playing with wall street. I skews the capacity numbers to keep wall street happy for this year. It shows capacity discipline, Wall street's 2 favorite words after non-union. They reduce capacity this year and increase it next year with more airframes. I am not sure how it exactly breaks out but they can find a measure like seats available and massage the numbers.
Another thing this allows delta to do is reduce the airline in the shoulder months to increase the flying/capacity only in the summer. They have done this in the last few years with there in-flight premuim cabin upgrades and heavy checks.