I've read attentively. Then explain why do you count price 210 billions but not 299?? why do you use the price on 2002 year but not current price??
Because it isn't a current price, it's a "then year" price. That is, each dollar spent is at the prices of the year in which it is spent. For past years, it's actual money spent. For future years, it's a prediction, calculated by predicting
1) how many JSFs will be bought each year
2) what the constant-price cost of each one will be for each year (that is predicted to change over time)
3) what the general price level will be each year
and combining the predictions.
If inflation is not exactly as forecast, or the pattern of purchases changes (e.g. 100 are bought in year X & 200 in year Y, instead of 150 in each year), so will the "then year" price, even if the cost in constant dollars remains unchanged. It's therefore an artificial number, dependent on three predictions any or all of which may be wrong.
The constant dollar costs are not fixed, only the denominator in which they are expressed. If general inflation is 5%, & JSF costs go up by 10%, the constant price JSF cost goes up by 110/105.
Because of the way it's calculated, one can't apply a simple conversion ratio to the "then year" price to turn it into, e.g., 2008 prices, but one
can apply a simple conversion ratio to the 2002 price. The conversion ratios are online in the US budget, & the latest ratios are at
http://www.whitehouse.gov/omb/budget/fy2009/hist.html - section 10, click on the link. Excel spreadsheet.