>You need an entrepreneurial mindset to tell the difference..
No, you don't. Why would you? You think too little of the average human. If you can communicate the chain of logic that led you to make the change. That should be sufficient.
There needs to be the freedom to make this type of change, but you still need to be held accountable for your work. It should be ok to say 'we ended up building something different than we were expecting.'