the calculation is very simple. you have 2 matchday wins (day #28 and #31) and bullrun2020bro could get the most points on matchday #27 and #31. but the difference is that bullrun2020bro was the only winner on day #27 and didn't have to share the matchday win with other participants, like in your and bro's case on day #31.
In addition that if you check the scored points on these match days. I won mine with 22 points, while you scored 12 on yours. The other one we both did 14 points.
Source: Kicktipp
If the points had been equal, kicktipp would have automatically put us both in first place, but for obvious reasons that was not the case.