II. modeling BIND (cont.): asymmetric loads

why does A get 2X the query load of B..M

if BIND4/BIND8 and modern BIND9 are still dominant query sources
                then they are hitting A..M somewhat evenly, with small localizations 
                according to RTT variance seen by various client populations.

A's additional ~3Kq/sec in volume from where? 
as yet uninvestigated