Yeah pretty much that seems how it works but maybe should write more adequate what I wanted to say - within 1 and 5 multiplier there are thresholds when the enemy's difficulty is changing to higher (remember da skillz of Quick Play AI?

)
About FS, I meant that e.g. with 6 streaks/multi x2,5 U will see teams with 150% FS of Ur team. Despite the fact that with 0 streaks/multi x1 the opposing team have following FS pattern: noticeably worse, slightly better and just slightly worse. And that pattern repeats even when lobby will suggest team will FS far from yours.