Really, I don't think that the developer is "making excuses" here. Which makes it all the more unfortunate that the letter as written sounds like excuses.
> The next question will be, "Why does it take 4.5 hours to manually test?"
I'm not sure it will. In my experience, clients are usually surprised about how long something takes not because they think specific tasks are taking too long, but because they aren't really aware of what the tasks are nor of their tradeoffs.
"You're right, it took longer than expected. I chose to spent some time setting up automated tests. That took extra time now, but will save much more time later."
> The next question will be, "Why does it take 4.5 hours to manually test?"
I'm not sure it will. In my experience, clients are usually surprised about how long something takes not because they think specific tasks are taking too long, but because they aren't really aware of what the tasks are nor of their tradeoffs.
"You're right, it took longer than expected. I chose to spent some time setting up automated tests. That took extra time now, but will save much more time later."