Yes, Noel. I'm afraid it is a bit of a myth! The whole Kadee/NEM process is a bit of a mess, the pockets are often WAY off the correct height and I find the swivelling cams that Murphy and Bachmann use don't play nice with Kadees either.
If you're really serious about switching to Kadees I think you have to bite the bullet and fit them permanently, either to the body or to the truck/bogie.