As we all know, lead by example can be pretty powerful in combat (+14 to every action of every marine and a reroll to one person each round is very strong (admittedly with a tactical ultramarine leading with loads of command and high fellowship, all possible at rank 4)).
However, it's out of combat it seems even more powerful. As written, it seems to be that with just the activation of the power at the start of the mission every narrative time action the group does is at +14 and because there aren't rounds, everyone gets a reroll to every action (ignoring actions that happen simultaneously).
This seems extremely powerful, as effectively a marine that has 35 in a stat is better with lead by example than another at 70.
(Normal character, chance of passing a challenging test - 70%)
(Marine with lead by example, chance of passing a challenging test - 49% - With reroll - 74%)
Am I reading the way this ability works correctly?