Just a quick note. I had a few day's loan on a really wonderful little Fluke DSO that could show the waveform across the load and the shunt resistor simultaneously. What a wonderful little instrument. It is not compatible with my flash drive and unfortunately I was unable to give you copies of that waveform.
What was evident was a small phaseshift between the two but their essential shape is the same - both moving above and below zero. I'm hoping I can secure another one for our demo. Meanwhile I'll post the photos that I did - unfortunately also not that clear. I still need to upload them to photobucket.
Sorry we can't give more info here.