If you’ve had good experiences w/this shop otherwise, I think that’s probably a fair deal. Their reasoning I expect is that no matter what they did, it may not have been possible to remove the ball joint w/out breaking the steering knuckle in the process. Due to corrosion of the parts or whatever. The reason they are not asking you to pay for the entire steering knuckle replacement is that
- they’d prefer to continue to have your future business
- there may have been a way for them to prevent the part breakage if they had been willing to take longer to do the job, like perhaps soaking the parts overnight with an anti-rust product, but then they wouldn’t have been able to deliver the vehicle back to you on time, which they didn’t want to do as you probably need to use your car on a daily basis to get to your job etc. Taking an extra day to do the job might have worked, but also might be penny wise and pound foolish.
2008, 9 year old car, if the repair is working now, I suggest you agree to what I think is a fair compromise.