In the previous tiers final rankings were defined by timestamp of the final bosses kill (Madness of Deathwing in Tier 13 and Ragnaros in Tier 12).
In this tier we have several gated final bosses and final rankings will be defined by total of the scores.
We are switching score by date to score by seconds in order to get more accurate ranking for top guilds.
The downside of this change is for average guilds the rankings will now depend more on their raid schedule. Those who start raids earlier will get more score points.
(This is why we didn't want to do that before)