Flat rate charge?

I have an IPhone 7 which experienced the “No Service” issue. When researched I found it was a known issue that can be fixed for free due to it being on Apples part. I had no damage on the phone, still nearly new, but while going through the repair before signing I noticed the $319. I was informed it was incase they found any other issues with the device and that it’s standard, but if the phone has no other issues it will be $0 but the system won’t allow them to do just a free repair.

Is this normal? I normally go to my carrier where I have a repair plan but the Apple site states they cannot fix the issue.