Hello Deniz,
find below explanation....
If you set the group indicator for a condition type and do NOT use a group condition routine, the system responds as follows in the standard system:
a) To calculate the scale base value of the condition, the scale base values for all items that have a condition record with the same condition type and with the same variable key are added AND
b) For percentage conditions, a rounding distribution is performed so that the value calculated for the entire document matches the total of the item values. To achieve this, a difference that may exist is added to the item that has the largest amount.
Thanks