No requirement states you have to do one first.
If you do drive-thru first, you add a minimum or 5 extra minutes to your shop. Guidelines state if you perform drive-thru first, you cannot enter the location for the dine-in for at least 5 minutes after completing the drive-thru. For dine-in, the requirement is to stay a minimum of 15 minutes after receiving your order.
If you do dine-in first, you can immediately perform the drive-thru after you hit you minimum 15 minute mark for the dine-in required time.
Shopping the Greater Denver Area, Colorado Springs and in-between in Colorado. 33 year old male and willing to travel!