There really isn't too much deep black in that scene unfortunately. Printed material with plastic wrapped around them probably aren't the best test cases?
Anyways here is ISO 3200 comparison to the ISO 100 pulled 5 stops. The 7D2, for an APS-C, does very well, substantially better than the 7D, and I think even a bit better than the 5D3. But you can definitely see the color casting in the pushed ISO 100, and the color differences. Faster shutter speeds really help, lol.
forum: Canon EOS Digital Cameras
I think your math if off here. The push is about 1.5 stops pushed more than the 3200 ISO exposure. (3200 was 4 stops over ISO 200, but then you gave back almost a stop going from 1/25 to 1/15 sec.)