I know nothing about this topic, But I think your accountant was talking about R&D tax credits, which is a different topic from R&D capitalisation and depreciation. The tax credits might be another reason why companies previously wanted to claim developers salaries as R&D.

The issue here seems to be that software development wages are now supposed to be treated as R&D per https://news.ycombinator.com/item?id=35620164 and I am guessing that the IRS wants R&D to be capitalised with a standard depreciation schedule.

Hopefully someone who is an accountant can ELI5 this all, because this topic is mostly basic accountancy. https://news.ycombinator.com/item?id=35614721 explains it a bit, but misses the ELI5 part about what amortisation/depreciation is.

A good example that is about building a thing rather than some software would help. Edit: Best example with good child comments so far: https://news.ycombinator.com/item?id=35615217