It sounds to me like the problem is that the game doesn't "put sons under other sons".
So if there are 4 brothers and 2 duchies,
Main Heir - Duchy A, 3 counties
Second Heir - Duchy B, 3 counties
Rest of 2 Heirs get 1 county each inside Duchy A.... Leaving Main Heir with 1 county + Duchy title, and Second Heir with 3 counties + Duchy Title.
When the solution would have to be:
Main Heir - Duchy A, 2 Counties
Second heir - Duchy B, 2 counties
third Heir - 1 county in Duchy A
Fourth heir - 1 county in Duchy B
So if there are 4 brothers and 2 duchies,
Main Heir - Duchy A, 3 counties
Second Heir - Duchy B, 3 counties
Rest of 2 Heirs get 1 county each inside Duchy A.... Leaving Main Heir with 1 county + Duchy title, and Second Heir with 3 counties + Duchy Title.
When the solution would have to be:
Main Heir - Duchy A, 2 Counties
Second heir - Duchy B, 2 counties
third Heir - 1 county in Duchy A
Fourth heir - 1 county in Duchy B
- 3
- 1