low res bush can't be replaced with hi res bush for rendering using particle system

I’m doing a tutorial here: http://davidallenward.com/category/tutorials/ I created hi and low res placement foliage for my particle system. I am unable to substitute the low res bush for the high res bush. When I do, in the mesh data menu, the low res bush disappears, but the hi res bush doesn’t take its place. The other foliage worked as expected. Can someone tell me what I am doing wrong? And how to fix this?

Showing the high res foliage on layer two.
http://i846.photobucket.com/albums/ab27/blanco1111/help15_zpse40e2970.jpg

Showing the low res placement objects on layer four:
http://i846.photobucket.com/albums/ab27/blanco1111/help16_zps8a553a64.jpg

Showing I was able to substitute the low res placement foliage in layer four with the hi res object object data panel. Except for the bush.
http://i846.photobucket.com/albums/ab27/blanco1111/help17_zpsc93427e7.jpg

Blend file http://www.pasteall.org/blend/27031