I don't have the answer to your question, but I'm curious of the answer as well. What I do know is that 3 or 4 years ago when I purposely sought out with intent of purchasing a malt that was marketed as "undermodified", I couldn't find any, so I ended up decocting a highly modified malt instead.... and the results were excellent. I like doing things authentically, for the fun of it, but of course in the end it is the taste that really matters. If we find an undermodified malt, though, I'll want to run some more experiments.