Actual Overhead Cost Splitting

Dear All,

We have 5 direct activity types and 3 overhead activity types in the system.

Plan Overhead cost splitted perfectly aginst the 5 direct activity types based on the activity quantity,

but when it comes to actual splitting:

1.the system splitting the cost eually in NEGATIVE among the 5 direct activity types instaed of splitting to 3 overhead activity types

2. system considering the all direct activity cost as part of one overhead activity types.

I am unable to understand how the system is behaving while splitting actual overhead costs to direct activity types

Can sombody throw any light on this issue.

Regards

SU