On page 284 is the Threat threshold introduced to create 'balancing' encounters. What eludes me however is what it actually is. On first glance it looks like that an encounter for e.g. 6 rank 5 PCs should be 12*6 = 72 NPC's but that short of ridiculous.
So how should I interpret it?
The threat threshold is a number that limits the maximum
number and strength of NPCs that should be included in
an encounter. To determine the threat threshold for an
encounter, use the encounter rank on Table 12–1: Threat
Threshold on page 284 to determine the multiplier for the
total number of PCs in the warband. The result is the threat
threshold, which should be modified as needed should the
Acolytes have NPC allies aiding them or other factors.
Using Threat Threshold
Once the threat threshold has been determined for an
encounter, the GM can start creating the encounter by
adding NPCs. As the GM adds NPCs to an encounter
he adds together all of their threat values. Ideally, the
combined total of all threat values in the encounter should
equal the threat threshold. However, this is often difficult to
accomplish. If the total threat value of an encounter exceeds
the determined threat threshold, the GM should recalculate
the rank of the encounter.