That's also the beauty of Fast.com, that it uses the Netflix content servers as benchmark and not some ISP edge hosted Speedtest server with special priority.
That gives a more realistic expectation of how Netflix, and in this case Apple downloads, will actually perform. And it can't be artificially boosted by the ISP.
That being said, I assume both Netflix and Apple have very special CDNs with ISP co-located content servers in many cases so it is still not a realistic measurement of generic Internet performance (but Speedtest is even worse, so ¯\_(ツ)_/¯)
That gives a more realistic expectation of how Netflix, and in this case Apple downloads, will actually perform. And it can't be artificially boosted by the ISP.
That being said, I assume both Netflix and Apple have very special CDNs with ISP co-located content servers in many cases so it is still not a realistic measurement of generic Internet performance (but Speedtest is even worse, so ¯\_(ツ)_/¯)