I have a heat press where the temp is set and displayed on the control panel. I put a infrared thermometer on it and it was reading almost 20 degrees higher than the display. Now, my question is with the shirts I have done, would there be any problems that would occur in the future because the heat was higher than the recommended? Also, what are the visible results on the garment if the heat is too high or too low? Sometimes, I have noticed that the vinyl is shiner, than other times. Is this due to over heat? Thanks for any help.