Without giving too much away, consider this board:
Duchess, Fool's Gold, Pawn, Secret Chamber, Develop, Lookout, Rats, Scavenger, Cartographer, Counting House
How would you play it?
The straightforward play is "Fool's Gold with a +buy". Pawn is a weak +buy for FG, but not terrible. Not reason to to open Pawn+FG, try to win the split and then follow the standard FG strategy.
But there is something else in there that is a lot more complicated that may beat the straightforward play.
Can you see it?
I'll post the solution tomorrow or later today.
Ed