This is why cost is a tricky subject. When you look at costs in terms of real dollars and you take inflation out of it--constant-year dollars, 2010 economics--then you get a time-phased and continuously reducing curve.
If you look at the effects of inflation and calculate that same cost in then-year dollars, there's a point at which the cost curve gets flat. You're building the same quantity every year, year on year, you've learned how to build the airplane, and your suppliers are at the peak of their performance. Then you have a tail-up that occurs, which is inflationary, whatever the inflation increases are out in time.
You have to be specific as to whether you're talking about future-year dollars, current-year dollars, or constant-year dollars in the past. All three get very much jumbled up in the cost discussion on this program.