[AtlUmpSteve]

IMO, the "last time by" concept contradicts the requirement to touch bases in the proper order. If one must touch first, second, third, then return order must third, second, first. If one must retreat to first and misses second, the only way to remedy would be to go back to touch second, AND THEN go back to first again; only after retouching ALL in the proper order could one again advance to second and be safe there.

At least, that's how I learned it; and the case plays in all these posts above seem to lean in that direction.