I inserted the instant thermometer in the turkey about one hour in the cooking as someone of my family suggested. It took about 3 hours to reach 163, struggled after 150. I was expecting 2.5 hours or so.
When we were cleaning the kitchen, we noticed something wrong with the thermometer. Its clear cover over the meter was melted, and its needle got stuck. The cover is made of plastic, not glass!, to my surprise. That why it took more than I thought. Now, I am really glad that the turkey was not over-cooked. I guess I have an issue with the thermocouple recently (Oxyprobe is the thermocouple, too.) Do things always come in three’s?