FFF's explanation is the way i see it.
I did the FAA IR and ATP,the ATP ride needs to have a non precision approach in it, so we did a localizer approach!That should tell you enough.
When i converted back to the UK i had to start all over on my NDB work,Dip,30 Degree Gate's,extended procedure,coastel effect bla bla bla.
It took some hours in the FNPT and in the plane to get to exam "level".
Jimmy as a instructor i trained a lot of students for the FAA IR/ATP your exam is not very realistic but it makes a good bar story.
Yes,AlexEvans the FAA IR is a lot easier.
Cheers