Just adding one extra information, building the playlist on our side enabled us to define the DVR window (how many time one can seek back on the video). Since we built both the server and client side, it was also possible to add tags to the stream and we did it. tl;dr; It was possible to control the adaptive streaming on the server side.

When our CDN was very crowded, one tag on the HLS playlist was able to direct users to a lower quality, preventing all the users to fight for the same bandwidth and avoiding rebuffering events.