Caching SERVFAIL?

I got this patch (djbdns-dnscache-NCACHE.patch ) via Jason Haar:

Author: [email protected]
diff -pr djbdns-1.05.orig/query.c djbdns-1.05/query.c
*** djbdns-1.05.orig/query.c	Fri Mar 10 15:07:10 2006
--- djbdns-1.05/query.c	Fri Mar 10 15:08:27 2006
*************** static int doit(struct query *z,int stat
*** 211,216 ****
--- 211,217 ----
    if (state == 1) goto HAVEPACKET;
    if (state == -1) {
      log_servfail(z->name[z->level]);
+     cachegeneric(DNS_T_ANY,z->name[z->level],"",0, 200); // For 200 seconds
      goto SERVFAIL;
    }

I think this is the problem Dinesh was trying to solve:

http://marc.info/?l=djbdns&m=113760199401605&w=2

Jason's problem:

http://marc.info/?l=djbdns&m=114192951031335&w=2

I started looking at RFC 2038 (NCACHE), but my eyes glazed over pretty
quick.  It seems to me, however, that this patch is addresses only
section 7.1 - Server Failure (Optional).  Comments?