How do the Rankings on the Guild vs Guild Leaderboard work?

My Guild planned out a massive Raid assault for the beginning of this month so we could get off to a fast start and see how high we could rank. Yesterday morning, May 1st, we opened up the Raids and knocked off one after the other. Almost immediately, we were ranked #1 on both Leaderboards and after a long day of Raiding, we had more points (1200) than any other Guild and we're ranked as the #1 Overall Guild. In no way am I saying we are the best Guild, but it's a cool way to bring the membership together, get everyone involved and after the same goal. We had a lot of fun and guys were really excited about getting to that top spot regardless of how long we stayed there. But what happened to us yesterday makes zero sense and I believe I can prove it. But you tell me if I'm wrong, that's always a possibility. So I have a screenshot of my Guild, The Event Hørizøn, being the lone Guild with 1200 points and ranked #1. I also have a screenshot from a few hours later when another Guild caught up and tied us with 1200 points, but for whatever reason and despite only tying us with 1200 points hours later. The Guild "Shatterpoint" was now ranked #1. We got pushed down to #2, then later on #3 when someone else tied us. I know it doesn't really affect anything, but it still doesn't make sense to me and I will always fight for my members to get what they deserve. And after what we did yesterday and the way we all came together, I felt like we deserved to hang onto #1 until someone had more points. That's all, even if there were 3 or 4 #1's because of time zone advantages. That's fine, but why were we ranked 3rd? That's my issue. I'd really appreciate any help or info about how the rankings work so I can at the very least give my membership some sort of explanation. The screenshots clearly show that we were the first to 1200 Raid points but knocked out of 1st place when another Guild tied us.