The conform to scaling only works when the item is being conformed.

The V5 figure comes in zeroed - so it is effectively Genesis. V5 itself has scaling applied to the figure itself and bodyparts - this is if you turn the V5 morph on. Since you currently cannot conform the clothing to the figure, I have no idea if scaling is done in the clothing (which was a V5 clothing item).

I'll guess I have to wait for the next update of the exporter before I can use clothing and to see how it works