This won't answer all your questions but hopefully this can help explain the "why" part. Here's a part of an article I found, it's not the same as your situation but hopefully it can explain it a little better...
Normally, it is possible to get pregnant when you only have one tube and one ovary that are opposite from each other. In fact, in nature, the egg ovulated from one ovary, say the right side, does not necessarily go into the right tube. This is a misunderstanding. The Fallopian tubes actually hang 2 cms (1 inch) down below the ovary and the egg can be ovulated from any part of the ovary. In reality, the egg is expelled from the ovary with all the fluid that surrounds it in the follicle. That fluid rushes out taking the egg with it. It then falls into a space called the culdesac located behind the uterus, where the ends of the fallopian tubes hang. Then by simple fluid motion (think of a spec of dust in a small puddle of water), the egg either contacts one tube or the other. It does not always find a tube. So in this way, it can contact either the right tube or the left tube and in your case, it can contact the opposite tube.
Okay, I just found another article that might help.
What causes ectopic pregnancy?
Delayed passage of the conceptus to the uterus. The conceptus may be fertilized in one tube but cause an ectopic in the opposite tube because it reaches that tube via passage through the abdominal cavity or through the uterus and back across into the other tube. Because of the increased amount of time required to travel these lenths, the conceptus becomes too big to complete its roundabout trip to the uterus.
If I'm reading that right, then maybe the fact that you ovulated from the opposite side as the ectopic did affect the results. I dunno, hope this helps!