CAP calculation on CIP balance for Common Cost tasks - bug or standard behavior

For common cost tasks, the CAP interest program will pick up the CIP balance for that common cost task as long as the expenditure line is is not in "unassigned" status.  Once the Generate Asset Lines program runs,  if the expenditure lines goes to "unassigned" status, it is ignored in the CAP interest calculation.   If I rerun the Generate Asset Line program to not pull in the common tasks, the line is removed from the Asset Lines as "unassigned' and will be included in the CAP interest again.

Is this standard behavior?  

Thanks

Peg