Once the story has
been played out, the storyguide awards
Adventure experience points in the usual
fashion, and an equal number of agency
experience points are applied directly to
the strength of the Bond, using the same
progression as Arts on the Advancement
Table (ArM5, page 31)
Then in Lords of Men on page 25 it says:
When the principal
earns Adventure experience, he simultane-
ously earns an equal number of Agency ex-
perience points, which are spent to increase
the agent’s Bond score using the same pro-
gression as Abilities (see the Advancement
Table, ArM5, page 31).
Sadly, I think Lords of Men (2011) takes precedence over HoH: Societates (2009). I have not checked the Definitive Edition.
[Edit:] Ezzelino points out below that the ‘ability’ approach in Lords of Men may be a typo, and I tend to agree. But it seems like there is no official errata on this. [/Edit]
Considering that agent Bonds are personality traits and thus ought to have scores in the same range, and that the maximum Bond strength is +6 (HoH:S p142, "Resistance of Agents"), it would seem that increasing the Bond score as an ability is more suitable.
For what's worth, I think that in LoM p.25 is a typo. It talks about agency experience points, and those are gained in the same way (same number of xp gained in an adventure that substantially aids the agent) and spent on an Art scale when recruiting agents, erasing their resistance (essentially a negative bond score). It's just an ungainly mess if they then slide to Ability scale when improving bond scores. HoH:S has it right and treats everything on an Art scale. Also, it is really too onerous to improve bond scores if you treat them like Abilities rather than Arts: an epic adventure (10xp) undertaken to help out an agent would at most be able to raise his bond score from +1 to +2, which seems far too little.
I had assumed that using the different experience cost scales was intended to make it more difficult to reduce Resistance than it is to improve the Bond score. So, you spend more time on Stories where you’re trying to recruit a new Agent, but less time on Stories where you’re maintaining your current Agents.
But LoM as written works in exactly the opposite way: reducing resistance is fast (works on the Art scale), improving bond score is slow (works on the Ability scale)!
Oh, I agree there’s an error in that the two are contradictory! I just don’t think that the design intent was for both Resistance & Bond to be on the same experience scale. I suppose which should be Accelerated or not would be down to what kind of stories you want to tell about Agencies. (at the moment in my game they’re just trying to recruit their first Agent so I wouldn’t want his Resistance to go away too quickly…)
I'm not on errata duty anymore, now that ArMD is in final layout.