bottom rear framing question

 I am trying to figure this out:

The very bottom of my back skin actually sat on the bumper supports- there were no cut outs for the metal bumper supports (like in the front skins- where there are notches cut out)  

IMG_0618 by kathy, on Flickr

However, the bottom of the side framing was actually below the bottom of the back skin. They seemed to have rectified this by adding a piece of metal to each side of the back to make up the difference. (Make sense?)

You can see the bottom of the back skin here- and the added metal underneath it:
IMG_0561 by kathy, on Flickr
Each side in the back had this:
IMG_0626 by kathy, on Flickr

IMG_0623 by kathy, on Flickr

I have added a piece of wood across the very bottom of the back- so I can attach the skin bottom to it.
IMG_5678 by kathy, on Flickr
As you can see- this piece does not match up to the framing on the sides at the bottom.
IMG_5680 by kathy, on Flickr
IMG_5676 by kathy, on Flickr

How do I manage this difference? Would you add the metal pieces back that were there originally? Or would you cut out notches in the bottom of the back metal so that its bottom matches the bottom of the sides?

I know this is hard to understand- hopefully you can see what I am asking!
Thanks
Kathy