Permission inheritence

I put my iTunes and Pictures folders under /Users/Shared so that I can sync my library and pictures to both my wife and my iPhones (we have 2 logons).

This is what the permissions are at by default to the /Users/Shared folder

/Users/Shared
- System - R&W
- wheel - R&W
- everyone - R&W

This is what is set at /Users/Shared/Pictures after I added myself and my wife (nothing else was changed)

/Users/Shared/Pictures
- me - R&W
- wife - R&W
- wheel - readonly
- everyone - R&W

However when I add new photos into subfolders of this folder, the permissions are not inherited from Pictures, instead this is what I get:-

/Users/Shared/Pictures/test
- me - R&W
- wheel - readonly
- everyone - readonly

So as you can see the wifes permissions are not their and everyone has changed from R&W to readonly.

I have tried CMD+I and running the setting "Apply to enclosed items".

This seems to fix it but then next time I add another subfolder to /Users/Shared/Pictures the same happens again.

Any ideas? It seems as inheritance isn't working (or not at least how I expect it to)??

Thanks in advance.