Okay, I think I found the problem. Take a look at this photo:
Notice the difference in the angle of the plate and the mounting ring? if the ring was flush with the plate it would be at an angle where the tank would not interfere with the distributor.
Here is a close-up view:
Can the tub be bent so that the ring angle will align with the plate, or would that damage something? Just looks like a sloppy job putting the thing together. I really wish people would take more pride in their workmanship.