Correct me if I'm wrong; Diminishing Returns is not a hard "stun x number of times within x number of seconds and it will be resisted" but rather a "for every time you stun the % chance of resist goes up" right?

When I first started running Ifrit HM I got raged at for missing interrupts but I swear at least a few of my "misses" were resists. Stun would go on CD and while it was hard to see through all the spell effects I remember seeing the "fully resisted" prompt.