Yes, rotating by 90 is great idea and i definately like to try it, but unfortunately it is not possible to get to it as it is buried deep inside a car's dashboard (the photo is of a spare) and i'm not keen on dismembering the car.

I redirected the evaporator fan's airflow to force more air over the lower section, this helped, but given that reorienting the distributor is not so easy to do i wonder if there might be other solutions ??