Well AppleCare is terrible IMHO. On the phone most of them have no clue. If the issue gets escalated you have someone who understands the issue but cannot do a thing. Then you always end up in the Apple store and they will only become active if the issue is acknowledged by Apple and their hardware tests find something. All other issues are basically ignored. I am having kernel panics since 10.10.3 [1] and there is no way to make myself heard... Had to leave my MBP with them for 5 days and they didn't replace a thing even though it has full coverage.
In 2014 BootCamp was shipping on new Macbook Pros which broke Windows 8.1's installer. The version of Bootcamp was actually newer than the newest version available to download, but supposedly the older version worked, but you couldn't downgrade.
Anyway I gave AppleCare a call. Told them that bootcamp version XYZ was messing up Windows 8.1's installer and that the older version worked fine, and asked if I could downgrade. Essentially they told me to "call Microsoft for support with Windows." And that's all I could get out of them. Zero bootcamp supported offered, even if it is Apple's own software.
The answer in an Apple store was (paraphrasing) "we don't recommend Bootcamp, if you want to run Windows then buy Parallels Desktop."
[1] https://discussions.apple.com/thread/7000724