I understand what you are saying, but the particular heat block we just purchased has a well tube holder that is removable and reveals the one heat plate underneath. Since everything is metal, the heat will distribute evenly. Also, since you are only checking one particular well's temperature daily, then are you to question the other wells of that day? These well blocks are removable, and I remove them on our extra heat block to keep a saline bottle warm. What would happen is I returned the well block backwards. Then the thermometer was not in the correct place anyway. We also have processors that continually forget to move the thermometer after taking the temperature and techs that move the thermometers for their convenience. I was just trying to look at a standard of practice that would follow a proper quality and respected in daily use by personnel.