The Colonial Supplies executive order has always been confusing to me so I have never used it (until now!).  The first screen snapshot below shows what the Colonial Supplies executive order says and it shows a colony that currently has a Decay value of -37%.  After spending 30 control on this executive order, the second screen snapshot shows that the decay for the colony was reduced by 50% to -18%.

I suggest changing the text of the executive order to say "Making a large shipment of supplies to our colonies will reduce their decay rate for 25 turns."  I also suggest changing the number in the "Effects" section to be -50% instead of +50%.  I think these changes will make it clearer to players what this executive order actually does.