There should be more details about the villager. Looking at the save game file, and that cheif and bla is random each time you open the game, there maybe have a important level(or il), -5 to 5.
-5 to -1 is that they will make their parter's level less.

Example:
1m, 2 il
30f, 3 il
Chances:

13,14,15,16,17,18

Example 2:
1m, -5 il
20f, 1 il ( -4 il)

9,10,11,12,13,14,15,16,17,18,19,20,21

But, I could be totally wrong.