Yes, there are limits on L-R and Up-Dn. When you get to the end and keep turning, the snap noise tells you- "You screwed up!"
2 ft high at 100 yds is serious off parallell. Rather than wringing off the control knobs, would go back and check mounts. Fully seated? Tight? if front and rear rings are interchangable, try swapping them and see what happens.
And, as always......
PICTURES, MAN! WE NEED PICTURES!