Would appreciate some opinions.
Fan on or fan off, that is the question.

I do both Electrical and HVAC. On this particular job I am the electrician. I am wiring the controls on an old Hill ZER-5, 5 glass door, upright display freezer. It is set up for electric defrost. I have always understood that the fans should be off during the defrost cycle. The guy in charge of the refrigeration is making me wire it with the fans running continuously. He does not even want a fan control or defrost terminator on it. He tells me the coils will not defrost completely without the fans running, and of course I'm thinking the fans will move the warmth away from the coils.
Could someone with some experience with these please end my confusion?
Thanks