The Orioles have a solid bullpen to go along with a feast or famine starting rotation and an offense that is atrocious at hitting themselves or walking themselves on base. Therefore, in games where the score is close, the Orioles' solo or two run home runs help make the difference. In games in which the other team get more of a lead, the Orioles simply cannot put enough men on base unless they begin to chase relievers.
That is it. I do not know if it is correct. Why I do know is that somehow the Orioles are doing something that no one has done before to the extent that they are doing it. They are dominant in close games and positively atrocious in the others. Remarkable.
Here is a graph for your amusement depicting runs scored or giving over the course of a single game as a frequency:
Here is a cumulative run scoring chart, adding from low scores to high scores:
I am not sure if that informs us of much. However, you do see a shift where the Orioles tend to score two to five runs at a greater frequency than their opponents. They have also given up four scores higher than any they have produced this season. It may well be that this team is constructed to brilliantly split hairs.