What Determines if the invoice data is be populated to BI LINE DST UAR or BI LINE DST

Dear Billing expert team,

I am always confuse the way the billing data is populated in the various distribution table. We have some issue in the Billing system where the AR entries is not being generated for some reason. When we check the data, everything looks good except it has no entries on the BI LINE DST UAR record. Can somebody please advise what are the check point that might cause the system not to create the AR entries. What determines the system to populate the into the BI LINE DST UAR record.

Thank you All in advance!!

Thanks,