Hello;
The pathfinder works in cells, either a cell is blocked or not (or costs a certain number of move points or not). An object might block two cells in one location but only one cell in another depending on overlap. The path goes from the center of one cell to the next in the path it finds, not a straight line. So if you are two cells up and over 3 it has to go over and then up (you can set it to move catycorner which helps a little).
It doesn't find the path to the object, it finds a path to the cell nearest the center of the object. It starts at the cell closest to your start object. To move exactly to a place you need to use moveTo. Pathfinder only gets you to the nearest cell.
hope that helps.
yours
winkr7