I don't know if I've always been doing something wrong but I was never able to use pan/crop for this sort of thing.
If you have trouble with pan/crop then use track motion. Track motion is a bit annoying because you have to key frame for the entire project. The timeline for each track is from start to end so you want to zoom in really close on the timeline to be precise on your keying to change the track back to normal unless you want to keep the eight frames throughout the project.
For pan/crop I usually find that you can crop your clip around the part of the image you want but the placing them exactly where you want on the screen, the eight frames, is impossible. Again, I might be doing something wrong but it's really easy to use track motion for that part. If you don't know how to use track motion you can just look it up on you - tube, there are a ton of tutorials.
If pan/crop works perfectly then my problem is me and you can just ignore this post.
