The IRS should do a code review and see. That script you wrote at 3:00AM after waking up to your pager? That thing is going to be around forever and will have to be amortized over the next 2000 years. 5 years, you're getting off easy ;)
I expect that there will be some sort of code reviews by software experts in the future during a large scale tax audit. Because there is a distinction between regular software maintenance (including diagnosing and debugging) and an actual upgrade or enhancement. So it's not like you just capitalize 100% of the salary, unless it is clearly a support role. But even for testing and quality control, they make a distinction between before and after putting the software into service.
At least that's now how the IRS sees it. Similar to buying machines to create a physical product.
Maybe they read all these articles about developers working in a feature factory.