Modify the Acron model so that development lasts for an extra 3 years. Specifically, assume that development costs of $14 million and $4 million are incurred at the beginnings of years 1 and 2, and then the sales in the current model occur one year later, that is, from year 2 until year 23.

Imagine that in this model the sales increase, then stay steady, and finally decrease. The gross margin is $4 million in year 1, then increases by 10% annually through year 7, then stays constant through year 12, and finally decreases by 5% annually through year 23.