How do you identify which temp bill is associated with which "approved" bill?

When bills are approved on the billing worksheet and a "regular" bill is created:

1)  How do you know that the temp bill is "approved" ? We have found that PC_DISTRIB_STATUS = 'I' seems to be one indication, are there other fields ?

2)  How do you "match-up" the temp bill to the "regular bill"?

Thanks,

Varsha.