Anyone can make an EFP. There's nothing sophisticated about them. Flip through a copy of the Improvised Munitions Black Book (originally published for US Special Forces) and you'll see just how easy they are to make. All you need is an explosive and a container with the appropriate shape in order to direct the force of the explosion. So there's no reason to assume that EFPs being encountered in Iraq must have been made under the auspices of the Iranian government.
You may want to read more about the differences between simple shaped charges and the current generation of explosively formed projectiles. "Scientists use design models and shock physics codes to predict terminal shape of projectiles" does not sound like something you can whip together in your garage.