I dont think its the math. I think its the poorly worded and poorly understood difference of 1) is it from when you take the COVID test? Or when you receive the results? And 2) is it 72 hours from when you depart your first departure point (home airport)? Or is 72 hours from when you depart the final departure point (last leg) to Thailand? I have seen so many answers and variations it can make your head spin! 😆