No, not 25x more productive, try more like 1000x more productive. Or try this on for size, I've known quite a few engineers that had negative productivity ie if they stopped doing their job, their team actual becomes more productive. How many times more productive is an average engineer over an engineer with negative productivity? N/A? Infinity?
The amount of time it takes to write a piece of code isn't about the time designing it, or about how long it took to type in the code, or the testing, or the plan. The ONLY major factor in speed of development is the debugging time, which is a sum of a sequence of random variables of random length. For better engineers who might average 1/10th the number of initial mistakes in the code (ie the length of the random sequence), and who might also find and fix problems in 1/10th the time, you easily get 100x more productive than some average. Or more likely you work in a cube farm far, far away from those 100X and 1000X engineers who have the choice to work other places.