The Prenucleolus: 

x1 = 5
x2 = 5
x3 = 2
x4 = 2

Excesses:

3.55271e-15 (1 3 )
0 ()
-1e-06 (1 2 3 4 )
-1e-06 (2 4 )
-2 (1 2 )
-2 (3 )
-2 (2 3 4 )
-2 (1 3 4 )
-2 (4 )
-4 (1 2 3 )
-4 (1 2 4 )
-4 (3 4 )
-5 (2 )
-5 (1 )
-7 (2 3 )
-7 (1 4 )