QSPEC TMOD and packet header overhead

Hi,

probably a dumb question, but Max Laier and I could not find any
guidance on this in the qspec draft:
I guess that the TMOD-1 r parameter in draft-ietf-nsis-qspec-20
specifies the number of bytes/s for IP packets, including any
IP headers. Now consider a mobile node that adds extra overhead
to its data packets due to the mobility headers etc. This could be
significant for VoIP packets. So in this case the applications has
to increase r depending on the packet rate and m must be increased,
too?

As another example: if the application communicates via IPv4
it has to specify for a normal PCM codec VoIP traffic:
r=50*(20+8+12+160)=10,000 bytes/s
  [packet every 20ms,IP+UDP+RTP+payload], m=200 bytes,
  b= 2000 bytes, p=very high (allowing a burst of 10 packets)
and when communication via IPv6
r=50*(40+8+12+160)=11,000 bytes/s, m=220 bytes,
b= 2200 bytes

Is this correct? Would it make sense to provide a little
guidance on this and an example in the QSPEC?

Regards,
 Roland