Cause if so, fixing this may be easier then the other direction - normally when I get requests about the height it's to make them smaller. There's a number of different systems that each have their own dimensions to be compatible with them. Easiest way to get these the right size for hirst is to scale the Z by 158% (4mm up to 6.35mm ~= 1/2 inch). Most slicers can scale the axes individually.
Does this work for you?