Sounds like I should book two one-ways (another incentive not to book R/T) as soon as I know my plans, but not print until I'm sure. Since I'd be going through Albany the night before, I should know by then, and in any case it's <$6 (10% of 80% of $67). By putting WAS-NYP on a separate itinerary, I could cancel (if I got a ride back from someone, say) without penalty.
I suppose the way the rule is written, there's no concern about printing and then changing plans, since 100% would be applicable (unless the change involved a price reduction, e.g. from an Acela to a later Regional train).
Thanks for the info. I may ask over on AC forum about using Canadian card.
=aw