Your problem is that what you are trying to do is get FCP to generate 5 or 6 frames from the difference between two fields, or an inter frame break. It's like adding a dropper of paint to a gallon of thinner and wondering why the new color doesn't cover the old.
You need Red or Magic Bullet. Both work with optical flow technology designed to track pixel vectors and generate motion clouds.
We are talking a long render, and some serious tweaking to mask things for temporal analysis by the filters, but the results are miraculous.
Don't waste your time a second longer trying to bull through. You won't be able to.
Ian