acl_check_mime vs _content

I recently upgraded to the latest Exim + exiscan v 22, and my 
acl_check_mime scan is failing. If I run the ACL, I see this kind of thing 
in my logs:

>[216.254.0.204]:54437 F=<[email protected]> temporarily rejected during 
>MIME ACL checks: cannot test demime condition in MIME ACL

acl_check_content works fine though and I am using it to kick back .exe's 
and other suspicious file types, which is what I wanted to do anyway.

I am including my MIME ACL below, but the real question is -- should I be 
using MIME checks, content checks, or both? The content ACL checks file 
type AND has the hooks for SpamAssassin, so it seems like I can bag 
acl_check_mime but I want to make sure I am not missing anything...

TIA!

Cheers,
Matt

---------------------

acl_check_mime:

   # Do not scan messages submitted from our own hosts
   # and locally submitted messages.

   accept  hosts = 127.0.0.1:+relay_from_hosts

   # Decode MIME parts to disk. This will support virus scanners later.
   warn decode = default

       deny  message = $found_extension files are not accepted here
       demime = com:vbs:bat:pif:scr:exe

   accept

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Matt Staroscik * KF6IYW * [email protected] * http://wrongcrowd.com
"The combined weight of the horrors I have authored wrought would crush
your carbon hearts into perfect diamonds of terror."
                                         -- Leonid Kasparov Destroyovitch