So, when you did these experiments and you measured freezing rates, you made sure to notice that the mass of the water that started out hot was equal to the mass of the water that started out cold when it(the hot water) reached the temperature the cold water started at?

And, it doesn't make much sense, either, that hot water, once the molecules slowed down to say 45 degrees would then not have a very similar molecular structure and freezing rate as the water that started at 45 degrees thereby increasing the likelihood for the "igloo effect" to take place with the hot water as well. It defies not only logic, but common sense.