A bit of a belated reply, but I don't think this advice is correct.
The H440 has its own virtually enclosed PSU compartment. With a fan on the front bottom pulling air in, and sensible cable management, having the PSU fan face up would be best in my opinion. It would get the cool air coming directly into the PSU chamber from the bottom fan, meaning the air will be cooler than stagnant room temp air outside the case. Having the PSU fan facing up means it would pull this cooler air through and cooling it better than the air from outside the case.