You add the Guardian XP points with the reward when there is a Guardian Tournament active, that is totally wrong.
Always the Guardian XP points and the Reward are Equal when there is a Guardian Tournament active.
Last attempt …
The Guardian of Power of 3117 hit the Warlord lvl 9 and gain 2443 XP points, the Guardian XP 100% in NOT ACTIVE.
The next three hits are with Guardian XP 100% ACTIVE.
1) The Guardian of Power of 3117 hit the Warlord lvl 9 and gain 4593 XP points
2) The Guardian of Power of 3117 hit the Warlord lvl 9 and gain 4601 XP points
As you see the XP Point are about 88-89% more because the Guardian XP 100% Boost is active.
The Guardian XP points and the Reward are the Same as always.
So when a Guardian lvl 1 hit a Warlord lvl 20 and gain 9271 XP points without active Guardian XP 100% boost I expect that when I do the same hit with the Guardian XP 100% boost active 9271+ XP 100% boost= about 16500-17000 XP points.