Yea, that's 1 million per unit.

Burst streak damage is (sum of burst damage this turn) * {1 / (7 - #_of_bursts)}
So if it's a full burst? That's (sum of burst damage this turn) * (1 / 2), ie another 50% on top of things.

So if you hit exactly 1 million per unit with all 5 units, that's 5 million, plus a full burst streak damage of 2.5 million, for a total of 7.5 million. That is assuming that burst streak damage doesn't have its own soft cap.