use of "E" with adding headers

I'm considering using formail -I like this on the machine where my  
mail gets delivered (peak.org):

:0fhw
* ^X-Loop: procmail(_at_)informatik(_dot_)rwth-aachen(_dot_)de|\
  ^TOprocmail(_at_)Informatik(_dot_)RWTH-Aachen(_dot_)DE
| formail -I "X-Prefiled: procmail"

:0fhw
* ^TOnext-icon(_at_)gun(_dot_)com
| formail -I "X-Prefiled: icon"

so that when they hit my machine I can just check for the  
X-Prefiled header when it hits my (much older, slower) machine.

        Of course, I'd like to minimize the CPU impact on peak.org.  
 I've got an INCLUDERC setup with a series of these types of  
matches, each of which should only match once per message, so I was  
thinking that I should use the "E" flag, such as:

:0fhw
* ^X-Loop: procmail(_at_)informatik(_dot_)rwth-aachen(_dot_)de|\
  ^TOprocmail(_at_)Informatik(_dot_)RWTH-Aachen(_dot_)DE
| formail -I "X-Prefiled: procmail"

:0Efhw
* ^TOnext-icon(_at_)gun(_dot_)com
| formail -I "X-Prefiled: icon"

:0Efhw
*^TOomniweb-l(_at_)omnigroup(_dot_)com
| formail -I "X-Prefiled: omniweb"

Is this correct -- or should I do it differently (some sort of  
large bracketed thingy)?

NOTE: I am using a variety of fields in these recipes, ^TO, Sender,  
X-Loop, and others.

TjL

--
Tj Luoma (luomat(_at_)peak(_dot_)org) / http://www.next.peak.org/~luomat
Unix regular expression: (.*[^-a-zA-Z0-9_.])?)
Windows regular expression: "Damn.... it crashed again"
[If you have a NeXTStep|OpenStep web page, email me the URL!]