“Host message queue size, the spool table size or the tracking table size exceed the specified threshold”
As it is stated on “How BizTalk Server Implements Host Throttling” http://msdn.microsoft.com/en-us/library/aa559893(BTS.10).aspx, message Publishing throttling state = 6 could be raised due to the following reasons (one or all of them)
If the throttling condition has been raised due to spool or tracking tables sizes, all the host across the BizTalk group counters will have the 6 value even though the host responsible for throttling was just one.
This can gets you confused.
Since the Spool table is shared across all the hosts in the group, in case the system is throttling in this way could indicate that maximum sustainable load for the system has been reached (mixing data from all the host configured in the group... so... in this case it doesn't matter what host is causing the throttling and the system will reflect this fact by indicating throttling by all the host in the group) The same applies to Tracking tables (are shared across all hosts on the group)
The only case in which you will get different values for the host counters is due to Host message queue size.
Enjoy throttling ;-)