Platycephally (flattening) of the head is not necessarily if at all caused by infant sleeping on their backs but by how long babies lean their heads
against hard objects or, what I call, «transformer baby furniture, or furniture that can change into many different pieces (
like those transformer toys in the eighties and nineties) making it easy to keep babies heads
against hard surfaces for an excessive amounts of time therein reshaping the infant's head.