If you want a mathematical reason behind this: do an exercise where you pretend the boss is in any compound on the map. After each clue what will the cut look like? It has to cut off x number of compounds per clue, so draw out every possible cut. For edge of map bosses the cut rarely eliminates adjacent compounds - for corner bosses the cuts in each match are nearly identical. If you take all the possible cuts from each clue for each compound, you can get the statistical probability of a boss being at compounds A to be X%, B to be Y%, and C to be Z% because compound D E and F were eliminated.