To recap the question... "In a pinch, can you with any reliability reuse cone packs that haven't fallen the first go through?"
I really thought there would be more of a difference in the dropping of the two packs, but Noooooope.
Orton exactly.
I'm not advocating running cheap. Fresh packs are peace of mind that comes pretty darn inexpensively.... but... if you like to have a running idea of the heat work being done all over your kiln, sticking in a few undropped used packs would be fine... more or less.
Out of all of the great answers that everyone took time to leave, Subblea passed on a link that explained it dead on.
Thanks everyone! Now we need to try and blow one of those little buggers up.