Hi David,
Exception aggregation is enabled only for Formula/Calculated key figure .
Also, from your example, I am not seeing KF1 and KF2 are aggregating, are you talking about total result here?
aggregating by KUNNR and PLANT (with subtotals and total)
KUNNR PLANT KF1 KF2 KF3
=====================================
0000000001 1 4 7 113 (SUBTOTAL 0000000001 + 1)
0000000001 2 5 9 25 (SUBTOTAL 0000000001 + 2)
9 16 138 (TOTAL)