Thank you for the clarification. The incidents you mention regarding the specific companies of this regiment indeed seem to be well documented. The disparity in casualties taken at Springfield and Hartville is conspicuous to say the least. As a combat veteran and leader myself, it is an intriguing story to me. Combat tends to bring out the very best and worst in man. It's as true today as it was in 1862. I think the various possibilities you give as to why these men chose to react this way are dead-on. In my experience, failures such as this are almost always the result of poor leadership, and indeed it seems company H went on to serve admirably under the leadership of Captain Dickey when Berry was relieved.
Incidentally, do you know if the casualty figures from Prairie Grove reflect the same lopsidedness? I could not find a report of Confederate casualties from the battle broken down by regiments.