Sounds good to me. If I could spend 60 hours on developing the initial tooling, and if I could spend just 5 hours writing minimal code to get things working as I want, and spend the rest of the 35 hours on testing and making everything watertight, I'd call it a job well done.
Sure. I don't write any tests (luckily I don't work on a business-critical system), and 10% of my time is dedicated to fixing features that were broken accidentally. And now? 90% of my time is still dedicated to developing new features.
