The easiest fix would be moving the origin point to the center for all objects.
Alternatively, you will need to offset all path points by 16px. Say, find path to (NPC.X+16, NPC.Y+16), and when the path found - loop though all nodes and add 16px to them..
Or use a separate invisible sprite with the origin point in the middle for pathfinding, and pin your NPCs to it.