ball pythons may breed without being cooled but i would think that lowering temps before breeding season is to induce a build up of testosterone in males so that they may become more effective breeders. my ambient room temp naturally drops a few degrees during the colder months and thats about all the cooling i do. i also keep breeding males on the upper rack levels where the ambient temp is a little higher and come cooling time i switch them with lower level tubs to exaggerate the cooling for those specific animals.