This gets worse by the minute!
The helicopter does not takeoff "downwind" in this procedure.
The takeoff is initiated from a hover with a tailwind into wind i.e backwards. After all there is no such thing as a "downwind hover", it is just a poor execution of the english language.
The Bell mediums are more stable in a tailwind hover for a multitude of reasons. Think about all the connotations of where the wake from the MR is going.
As you increase the "tailwind component" the sync elevator will reduce the vertical fuselage drag component. Think Rutan aeroplane canard to point you in the right direction. This is only effective up to a certain point where it can get ugly. Have a little think about it.
Too long now but I think there may even be a little fine print that gets missed in the RFM about "rearward flight".