Need Explanation of DEF (Deferred) Analysis Type, and TMR Bill Status

PeopleBooks has skimpy explanation of the these topics. My understanding is DEF is created when an invoice date in the future is entered. Doc ID 1494835.1 states, "When BIL is switched to DEF, Billing Date needs to be populated. The PC_BI_TO_PC process changes the BIL to DEF and populate the billing date. CA_BI_INTFC process will pick the DEF rows only when the billing date is reached when compare to the date of CA_BI_INTFC process run." But I'm seeing DEF's being pulled into Billing Worksheet. Does the DEF Analysis type get changed to BIL or BLD? I know BIL changes to BLD. Also, TMR Bill Status. I see in PeopleBooks that it cannot be changed but does that get updated