Depending on the type of soy you have, based on experience, I find adding the oil at that low of a temp., will prohibit the oil from binding to the wax. Soy goes through a stage of crystallization while curing. If you add at a higher temp, you take the chance of burning off your oil and your soy may have a yellow tinge to it. 145 is a temperature that I have always found secure with my oils. Cure the jar for 24-48 hours or more then test for hot throw. If your not getting the throw your expecting, up the temp 5-10 deg. and try again.