As a context, here’s what I do:
When I have a Wanted: Heroes mission open, I reroll until I see a team I can beat. But rerolling puts you way above your pay-grade as far as your cup peers. I used to always reroll chasing cups, but sooner or later, I would find myself in a spot where all I see is teams with TP of 500+ above mine, and it takes some serious ham to reroll until I find a decent one. So what I started doing is rerolling when the mission is open and jumping at the first available opponent when the mission is resetting. That way, while the mission resets, I drop back to reality, where I belong.
Well, the problem is when I play for the mission, my boards suck. I lose against teams on my level and weaker sometimes. Sometimes it takes me 12-15 raids to get the 40 heroes. But as soon as I’m done with the mission and I start jumping on the first available team, I beat teams way above my weight class…mostly because of lucky boards. Is there something I’m missing? Is it just bad luck? Bias? I should probably measure it to be sure.