Sorry to revive a long-dead post, but here's a situation which happened to me today. Begin with 8 AP at square A. The path from A to C takes 8 AP, beginning with a diagonal step to square B. The interface shows me that this diagonal step to B costs 2 AP, so I infer that B to C costs the other 6 AP. Therefore I took two orthogonal steps (via a corporate safe) to B, leaving me with 6 AP, which turned out to be insufficient to reach C.