> Does "maintenance" on an amortized asset have to be amortized as well?

Usually not. Also, from other comments here, it looks like bug-fixing doesn't count as R&D (anyway, in a development focused company, you'll probably spend more deciding what is or isn't bug-fixing than you'd get from the difference).

Still, there are many more things that make software disappear just after being written. It's actually similar to most of R&D, so it makes little sense to count it the same way as capital investment.