Sometimes, there's a disparity between how you were taught in Advanced and how you should fly in the Fleet. Trust the IP when he tells you to do it differently <cough> trim <cough>. It might just save your life sometime.
That is an interesting discussion to have. Both the TH-57C and H-60 should be trimmed. The trim works differently in a turn though. After doing it myself, I spend hundreds of hours trying to beat the habit out of SNAs and IUTs to constantly want to move the cyclic. After learning to not move the keep moving the cyclic, I wish I had the opportunity to fly a H-60 for a few hours to see how my new flying style transferred back to fleet aircraft. I don't know if was based on aircraft or training, but I rarely had a problem with Marine IUTs not trimming out the aircraft. It was a noticeable difference.